SNES S REPRE CEN O WN TS SOR ORTON a HTL TRO eee eS
TOME AOE NE Ng Ee SON Ee OTE NERS NRRL PG CE ROY SNCS A RS CER ee
: Seattet SE SESS ee
eS Sa Ks.
aan
JOURNAL
OF THE
ROYAL
MICROSCOPICAL SOCIETY:
CONTAINING ITS TRANSACTIONS AND PROCEEDINGS,
AND A SUMMARY OF CURRENT RESEARCHES RELATING TO
ZooLtLoGyY AND BOTAN DT
(principally Invertebrata and Cryptogamia),
MICROSCOPY, &c. AIBRARY
Edited by
FRANK CRISP, LLB. B.A,
One of the Secretaries of the Society
and a Vice-President and Treasurer of the Linnean Society of London;
WITH THE ASSISTANCE OF THE PuBLICATION COMMITTEE AND
A. W. BENNETT, M.A., B.Sc., F. JEFFREY BELL, M.A.,
Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College
8. O. RIDLEY, M.A., of the British Museum, JOHN MAYALL, JUN.,
anp FRANK E. BEDDARD, M.A.,
FELLOWS OF THE SOCIETY.
Ser. IIL—VOL' IV. PART 2,
PUBLISHED FOR THE SOCIETY BY
WILLIAMS & NORGATE,
LONDON AND EDINBURGH.
1884.
The Journal is issued on the second Wednesday of
February, April, June, August, October, and December.
* 18 GSP a ; SRS DM WITS ;
EME inte te ne Saree te es Soe
DS Ser. IT. To Non-Fello
Vol.IV.Part4.} AUGUST, 1884. | Beies be.
JOURNAL
OF THE
ROYAL
MICROSCOPICAL SOCIETY:
CONTAINING ITS TRANSACTIONS AND PROCEEDINGS,
AND A SUMMARY OF CURRENT RESEARCHES RELATING TO
ZOOLOGY AND BOTAN YW
(principally Invertebrata and Cryptogamia),
MICROSCOPY, Sc.
Edited by
FRANK CRISP, LL.B., B.A.,
One of the Secretaries of the Society
and a Vice-President and Treasurer of the Linnean Society of Londen ;
WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND
A. W. BENNETT, M.A., B.Sc., F. JEFFREY BELL, M.A,,
Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College,
8, O. RIDLEY, M.A., of the British Museum, JOHAN MAYALL, Jon., —
anD FRANK E. BEDDARD, M.A.,
FELLOWS OF THE SOCIETY. }
WILLIAMS & NORGATE,
LONDON AND EDINBURGH.
CONTENTS.
2039300 —
TRANSACTIONS OF THE Sootmty— ae
--XI.—Reseancues on THE STRUCTURE OF THE Grrwitke OF Draroms.
By Dr. J. H. L. Flégel (Plates VIII. and IX.) .. . 605
XII.—On a New Microtome. By C. Hilton Golding ts (Figs.
SB adS4) ee aie ee meee uae Rui 823
XITI.—On somz ‘Mora Meanree IN THE BLooD oF Viesnuies Aviuaus
with Rerrrenoce To THE OocURRENCE OF BACTERIA THEREIN. ~~
By G. ¥F, Dowdeswell, M. A. FR. R. M. S., &e. on ee eur fe ee 625. P ;
~ XIV.—On ProrosrongiA PEDICELLATA, A NEW OOMPOUND Inrusorivm.
By Frederick Oxley, F-B.M.S. (Figs. 85 and 86)... .. 630
XV. —QOn a New Form or Powarizine Prism.. By C. D. Ahrens) =~
(Figs. 87 and 88)... .. wees, gareiee 533 :
Summary or Cugrent RESEARCHES RELATING TO oeigey AND! 4
Botany (pRincipaLLy InveRTEBRATA AND Cryprocamia), Mioro-
BCOPY, &c., INCLUDING ORIGINAL CoMMUNICATIONS FROM Frntows
AND -OTHBRSS 3 516 iset sony ves Vane et ae tee Sig ee —
te ‘ZooLoey.
Polar Globules and other Elements eliminated from the Ovum
Embryonic Germinal Layers and the Tissues... uiaiae
Origin of the Mesoblast of Cartilaginous Fishes ies
Intra-cellular Digestion in the Germinal Membrane of Vertebraies
Larval Theory of the Origin of Cellular Tyee A GLE
Development of Protovertebra .. .. . we
Eaperiments in Arrested Development .. .. .
Morphology of the Directive Corpuscles .. -s. ee. sn kt new SBT es
Morphology: of the Pineal Gland: (<0 ewe EE ye na wees
Segmentation of the Vertebrate Body =... 51 se se we
- Embryology of Alytes obstetricans .. Pe acter
» Development of the Nervous System of Forella Bes PP aay, :
_ EIneubation of Eggs in Confined Air — Influence of Venitation te aN
.. Embryonic Development’ .. Pa, F aeale
Effect of High Pressure on the Vitality of Miero-organions nes be
Micro-organiams of the Deep Sea... sey ereliGe vuera ine
Origin and Formation of Glairine or Baregine a
Organisms in Hailstones
Suckers of Sepiola .. Pee os woe) eld val sigue ent ee
Histology of Digestive System of Helis eee vik apis sales Somes oer ay lean
Aplysiz of the Gulf of Naples . iS Ake ee rahe
Morphology of the Acephalous Mollusen Le a iho
Anatomy of Rhopalea .. wins 's oat aime sein toe tei Mean ales
Luciola italica .. ..
* Development of Alcanthus niveus anit its ‘parasitic Teles.
Origin of Bees’ Cells . Es
Closed Poison-glands of Caterpillars Tdi Bae" tuy ext donee ae me vag eta
Gills of Insect Larve.. .. Sie esis ee alg alc ae ON
Dangers from the Hxcrement of Flies i ae
Nerve-terminations on Antenne of Chilognatha ie
Ovum of Geophili.... &
_ Poison Apparatus and Poison of Scorpions Oe
Structure and Function of the Liver of Renders vy
Anatomy of Acarina .. .. Hee
Sexual Colour-Variation in Crustacea
. Observations on Tanais cersteds ..
New and Rare French Crustacea
Nervous System of Euniceidz ..
Cerebrum of Eunice harassii, and, is relations to the ie Hypodermis
penis of Branchiobdella var tans
ee
ee ee ae ee oe ee ee
Loe oe oo)
as:
(38>)
Summary or Current Resrarcues, &c.—continued.
Ovum and its Fertilization (in Ascaris) ..
Spermatogenesis in Ascaris megalocephala
Spermatogenesis in Ascaris sag tg i
Nematoids of Sheep’s Lungs
wireptersng Nematodes = o-oo So Sou livsees Pian wet oe
Peeehan tt? GRA TPYICRINOaI8 06 56 ses Soe No Socs Be: Noe YS
Cystic Stages of Teniadz . eOee-eps est UN
Anatomy and Development of Trematoda. be
Worm-fauna of Madeira .. ..
New Species of Rotifer — .. de
Development of the Germinal Layers ae Echinoderms Saas wis
New Genus of Echinoids .. wide aah fae
Revision of the Genus Onda ono dee ong es vetiae
Organization of Adult Comatulide .. BPD as ACS 9h te bake hee
Anatomy of Campanularide +. 6. te te ee ne te
Structure of the Velellide .. 00 wee ee a
“ Actinizx of the Bay of Naples .. acetic g
Morphology and Anatomy fof Citiatea Infusoria gatas
Trichomonas vaginalis ., abe
Acanthometra hemicompressa
Orbulina universa PASS RSD ER a 7
Nuclear Division in Actinospheerium eichhornit. .. amiiee
Borany.
Homology se Ge Reproductive Organs in Phanerogams feiie bones
Influence of Light ‘and Heat on the Germination of Seeds Sohn oe
Origin of the Placentas in the Alsinex (Caryophyllez) .. 1...
Gemmz of Aulacomnion palustre. .. er
Relation between Increase and 8 eqmentation of Celle!
oe
oe
Development of he et ains in the Latietferous ot of the ie Buphorbiacee
_ Constitution of Chiorop.
Cellulose accompanying Me Formation of Crystals cpio eee
- Middle Lamella of the Cell-wall .. et
Intercellular Spaces between the Epidermal Calls of Petals . a
an Contents of Sieve-tubes .. igs Tey
_ Organs of Secretion in the Hypericacer lai aa gl ieknex Ronee es
agi Sa ea lh pacar dee: a Lig apt Viks wet TRGB Rett OA
_ Apparatus in Leaves for Reflecting Taye Mat: Snare StS
_ Swellings in the Roots of Papilionacee ., ba a Te wleg ake as
Origin of Adventitious Roots in Dicotyledones .. bets Kota patents
Crystals of Silex in the Vascular Bundles... 1 se se ss
Effect of Heat on the Growth of Plants .. 2. 6s ue ne ws
- Curvature of Roots te
Torsion as a Cause of ‘the Diurnal Position of ‘Foliar Organs :
Assimilative Power of Leaves ..
Quantitative Relation between Absorption of Light ‘and. ‘Assimilation
Canses which Modify the Direct Action of rig it on nents: v
Respiration of Leaves in Darkness .. .. Poa ae
‘Absorption of Water by the Capitulum 6 oebonie hayes
trons di Ma ay a A Te Ti ALT ie er
. Origin of Roots in TR Oy NOt ph Pee oT Oe eae
Oe EMonogtag h of Lote e
fs ge Position of Lepidodendron Sigilaria, | and. Stigmaria
’ any. ariations. in Sphagnum . “* ” ** * ad a
- Sexual oduction in Fun Geis, We tah) Se Mads ge Ke 1). ig
_ Life-History of Acidium bellidis DC. oo. (4abe) Bak
- Rpharopta and Affinity of Senere seer Boluvvinite ap i'o0 (lop
oc ew waa: on the Silver-fir . -- oe ’ ” oe ”
, ~ “Micrococcus prodigiosus within We Shell of an i Bag Prva Was oF
ig ood * : “* “* “sb
af Wat i * } ye ee - ’* * ”
Barbus of Chola ” oe ** “- -* “ee “* Re}!
KY . Virus of Anthras. - * “* oe ae * ” oo ” o
41)
Summary or Current Reskarouss, &c. —continued.
: _ PAGE.) >
Attenuation of Virus in Cultivations by Compresied Onygen ve ee ae OOD
‘Rabies... -<- we ee ee ee we 600
Bacteria in Canals and Rivers ee ue SSE aS ti ee)
Bacteria from Colowred Fishes’ Eggs sip owas ae ee oe d'or ein Sega) aol Ca
Bacteria connected genetically with Alge «sve ee ed te we oe COL
Action of Oxygen on Low Organisms =... xe we oe ne ne oe GOB
Biology of the Myxomycetes 2. se ng te te ee ee ae ee ee B08
Cephatodia of Lichens woo 30. emg en og ey) ee!) (Bat eg 2 we aaa ee = OU
Thallus of Lecanora hypnum saOy ap Ede Weeks aihale Unectee iat aw iat ree eee OLD
Systematic Position of Ulvacex BEA REE we eat ee ok cab pros aias etre eaetta ED
Newly-found Antheridia of Floridew .0 ve ue ae ne ee ee te 0G
New Unicellular Algz-. .. Se GR arel tne Pia Le wen Miele aa atROL
Structure of Diahower:.. 8 S50. Cee en ews Coaypi men mee eae + oe eee OES
Belgian. Diatoms .. a Es Gn,2 (an ancien ee brace eee eens
Didiomacer from the Island of ‘Socotra’. er he Lr ee ie en eh
Microscory. v chat
Microscope with Amplifiers (Pig. 89) -. 1d. Wi se bavi Rlpeas Vaan Maa deat
Bausch’s Binocular Microscope (Figs. 90 and 91)_ Be Meeurrna sweat Li
Sohncke’s Microscope for Observing Newton’s Rings (Fig. 92) Sipigae sas ec OUG
_ Harris and Son’s Portable Microscope (Figs. 93 and-94) >. vs a Se 611
Seibert’s No. 8 Microscope (Fig. 95) ws OLS 2
paca Large BS es Microscope and “Hand Magnifiers Figs. 96. AD is
and 97)... S 613°
Geneva Companys Dissecting Microscope (Fig. 98) Ee gen hee » 614
Drailimand Oliver’s Bie o0k? ee Mis: eee SU ere raa ynh pio ents vee ving at 07 &: Sige
Ward’s Eye-shade (Fig. 100) . : + Raa eye aimee ats eal oy Ii alps
Findomersion Objectives —... Fes bio bd ORAS ah te yids tod eee a erat aes 616.
Selection of a Series of Objectives sey pralul| agsericg ee OO reat
Correction-Adjustment for ‘Homogeneous-Immersion ‘Objectives +5. scape OSU
Lighton’s Immersion Illuminator (Fig. 101)...” sich cs thee
~ Illumination by Daylight and Artificial Laight —Parabeloids and Liebertiina 621
Bausch’s New Condenser (Figs. 102 and LOB) re oe hk aes ioe aerial aed
Glass Frog-plate (Fig. 104). 623 AR
Groves and Cash’s hs a for iMioresngat “and Phot AS
Observations (Fig. 105) ... .. 624.
Visibility of Ruled Lines .. Saree aaa eh no -3, 625. :
Mercer’s Photomicrographic. Camera ig. 106) Fe stacey ented Sue ERD
Photographing Bacillus tuberculosis ist Bei ake ibn ce Ups eee A St
- Beck’s,.** Complete” Lamp (Fig. 107)... GaP naphiny wae sieye
James’ ‘ Aids to-Practical Physiology’ 2. +. ee os ue a
Postal Microscopical Society .. Ree aap Meee Nt ta
Methods of Investigating Animal Cella ef ies Roe ae see
Born’s Method of Reconstructing Objects from Mictoecopie Sections Pan:
Shrinking Back of Legs of Oribatidz in Te ak ist Aes. oe ot dea Weteed Oaeeera
Preparing the Liver of the Crustacea .. Sere ga eae Rae eS
Preparing Aleyonaria... .. Eats t
Semper’s Method of making Dried Preparations . eC tole « O87
Method of Detecting the Continuity of Protoplasm in Vegetable Siriiciiecs < 687, a
Method of Preparing Dry Heo scopse Plants fos the eee eer tg Sn ORE
Chapman’s Microtome —_.. as :
Use of the Freezing Microtome . wee
ae for Injection—Fearnley's Constant Prewure Apparaiae ies
Myrtillus Yen ‘Staining “Aniintl and Vegetable Tissues . ia Gate tates tan
__. Hartzel’s Method of Staining Bacillus tuberculosis... |... we
' Safranin Staining for Pathological fens Ei eae
~~ Collodion as a Fixative for Sections ..
~ Piffard’s Slides .. ., ee Peierls
Mounting. in Balsam in Cells...
Styran, Liquidambar, Smith's and, van Hee ited
Grouping Diatoms .. aes
Quantitative Analysis of Minute Aerial Organisms
or ‘on =
Microscopical Evidence of the pate) of Articles ues Stone Sa
PROCEEDINGS OF THE Sociury
ove ee
Go)
ROYAL MICROSCOPICAL SOCIETY.
COUNCIL.
ELECTED l3sth FEBRUARY, 1884,
PRESIDENT.
Rey. W. H. Dauuinerr, F.RS.
VICE-PRESIDENTS.
Joun Antuony, Esq., M.D., F.R.C.P.L.
Pror. P. Martin Duncan, M.B., F.R.S.
James GuaisHeEr, Esq., F.R.S., F.R.AS.
_. Cartes Stewart, Esq., M.B.CS., F.LS.
| TREASURER.
Lionex §. BEALE, Esq., M.B., F.B.C.P., E.BS.
SECRETARIES.
Frank Crisp, Esq., LL.B., B.A, V.P. & Treas. LS.
‘Prov. F. Jerrrey Bern, M.A., F.ZS8.
Twelve other MEMBERS of COUNCIL.
AurgeD Wiiuiam Bennet, Esq., M.A., B.Sc., F.LS.
_ Roser? Brarrnwarrs, Esq., M.D., M.R.CS., F.LS.
G. F. DowpEsweux, Esq., M.A. -
J. Wit11am Groves, Esq.
Jouy E, Inarun, Esq.
Joun Marrnews, Esq., M.D.
Joun Mayan, Esq., Jun.
Auzert D, Micnann, Esq., F.LS.
Jonn Mrizar, Esq., L.R.C.P.Edin., F.LS,
Wiuuam Mirnar Orp, Esq., M.D., F.R.O.P.
Unean Pritcnarp, Esq, M.D.
Wuu1sm Tuomas Surrorx, Esq.
LIBRARIAN and ASSISTANT me eastaate
Mz. James West,
C65)
I. Numerical Aperture Table.
The “ APERTURE” of an optical instrument indicates its greater or less capacity for receiving rays from the object and «
transmitting them to the image, and the aperture of a Microscope objective is therefore determined by the ratio.
between its focal length and the diameter of theemergent pencil at the plane of its emergence—that is, the utilized’
diameter of a single-lens objective or of the back lens of acompound objective. ee
This ratio is expressed for all media and in all cases by sin'w, 2 being the refractive index of the medium and a the
semi-angle of aperture. The value of m sin'y for any particular case is the ‘numerical aperture ” of the objective.
88,688 | 1-087.
86,760 | 1*111.
84,832 | 1-136"
| 82,904 —
* Diameters of the Angle of Aperture (= 2). . Theoretical’ P :
Back Lenses of various : : Ilumi- |: Resolving » pate
Dry and Immersion Numerical = Water- | Homogeneous-| nating Power, in _ | trating
Objectives of the same Aperture. Ob ay Immersion| Immersion’ | Power. | Lines to an Inch, Power
Power (4 in.) (m sin w= a.) yieetives: Objectives.| Objectives. | (@%.) | (A=0°5269 @) (-)
from 0°50 t0.1°52.N, A. @=1) lm =1-33,)| (n= 1°82.) ‘sline BK.) | Na?
1:5 os xe 180° 0!) 2°310)° 146,528 |
1:5 ae a 161° 23’ |2°250| 144,600. |.
1:4 ee oe | 158°. 39! | 2-190). 1425672 | *67
1:4 BA 147°: 42?:| 2°132 140,744 | +68
1:4 A 142° 40" |2:074| 188,816"
1:4 we ob 138° 12’ | 2°016} °136,888 ©
1:4 * oe! 134°.-10" |1-960) 134,960. -
1:3 ais so + 180° 267) 1°904)-. 183,082. | +725:
1-3 os ‘ 126° 57’) 1°850|° 131,104 7}
1°3 : Ma 123°: 40’ |1°796) » 129,176 ©
1°3 as |180°° 0’) 122° 6’ }1°770) «128,212. 4° =7.
1-3 5 165° 56’| 120° 33} 1:742|> 127,248 | «=
1°3 ws 155° 38’|. 1179-34’ |1°690) 125,320:
» 12 148° 28’) 114° 44’ |1°638} 123,392 4
1-2 |. [149° 89°] 111° 59’ 11-588} 121,464 | -
1:2 oe 187°.36'| 109° 20’ | 1°538) 119,536 7)"
- 172 ae 183° 4'| 106° 45' | 7-488] 117,608 pas ee
~ 1:2 KG 128° 55’| 104°-15' | 1-440]: 115,680}
i ie b oe 125°° 3’). 101° 50’ | 1°392 113,752}. +84
1-1 <s 121° 26’) 99° 29' | 1*346)- 111,824 |. "862°
1-1 oa 118° 00'| . 97° 11’ |1°300 109,896 | +,
esded 114° 44/) 94° 56’.|1°254) 107,968 |: :
1-1 ate 111° 36'| 92° 43’ |1-210} 106,040 | *!
1:0 5 108° 36’| 90° 33’ |1°166} . 104,112 . |
1:0 Se 105° 42’| 88° 26' | 1-124] 102,184 | is)
“1-0 102°. 53'|- 86° 21' |1-082| »100,256 9) =
1:0 we 100° '10’| 84°. 18'-|1-040| 98,328 | =
zk 180°, 0’ |. 97° 31’) - 82° 17" |1:000}'~ 96,400 | 1-
O- 157° 2! | 94° 56’) 80° 17’ 960} ~ 94,472 } 4-4
QO: 147° '29' | 92° 24"). 78° 20’ 922) 92,544" [ods
& 140°). 6! | -89°° 564). 76° 24! | °884 90,616 | 1*064~
0-
0-
0:
0:
» oO:
O
62° 40’
60° 0".
TNANATDADHDOA AH IIITIINOD HON WOOOOGS
SVR AROVKHADOWHARDOWHADOWVPAHDOOHADOVMADOWOHADOWHHADOWRADOW
114° 17’ | 78° 20"). 67°. 6’ | +706} 80,976 | 1:190°
110°. 10' | 76° 8’| 65° 18’ | °-672 9,048 | 1°290-
0- 106° 16’| 73° 58’| 63°31 | -640
0: 102° 31’ | 719 49'| 61° 45' | <608
0: 98° 56’ | 69° 42"| 60° 0"! -578
0: 95° 28’ |} 67°. 86... 58° 16’ | +548
OF 92° 6! | 65° 32’) 56° 32’ | +518
_ 0- 88° 51’ | 63° Bl’) 54° 50’ | +490
0° 85° 41’ | 61° 30'| 53° 9’ | +462
0- 82° 36’ | 59° 30") 51° 298’ | +436
-0: 79° 35'| 57° 31") 49° 48’ | +410
0: 76° 38' | 55° 34’) 48° 9’ | +384
oO: - 78°. 44" | 58° 88’| 46° 30’ |. +360
- 70° 54’ | 51S 49") 44° 5 | - B36
0:
QO:
0:
trae ese ee tit
fixawpnr.—The apertures of four objectives, two of which are'dry, one water-immersion; and one oil-immersion, -
| HRAMP b Dich are’ = e oil-imm ie
_ > would be compared on the angular aperture view as follows i106? (air), 157° (air), 142° (water), 130° eae
Their actual apertiives are, however, ag Goan ; 480-> °° *98. 226 ) Fea or their
smumerical apertures: j : Uke iC aoe aaa
Gt)
; II. Conversion of British and Metric Measures.
Gi.) Lineat.
* Seale showing | Micromillimetres, §c., into Inches, §c, Inches, §e., tuto
the relation of | f ins. min. ins. | mm, ins. Ne raat:
ma iene | 1 000039 | 1 039370 | 51 2°007892 | — ins, i
&c., to Inches. 2 -000079|; 2 -078741| 52 2°047262 | _ 1 1-9]599)
mm 3 -000118| 8 11isll| 53 2°086633 | ~"2°" 1 -p¢9989
and 4 -000157| 4 *157482| 54 2°126003 | 77x" 1-693318
ny fe, 5 -000197| 5 196852 | 55 2°165874 | 1" 9-539977
n= ay 6 -000236) 6 236223} 56 2-204744 | 7°2°°. 9. g5o197
=e 7 -000276| 7 *9275593 | 57 2°244115 soso. 3°174972
[Ea | 8 000315! 8 -314963| 58 2°283485 | 2” 3-628539
lee | 9 +000354| 9 354334 | 59 2°322855 | —"v" 4-933995
= | 10 -000394) 10 (lem.) *393704| 60 (6cm.) 27362226] f°" 5.079954
EF | +41 000433) 11 -433075 | 61 2401596 | ac05 6° 349943
eee ee Be Oe
= 000512 | 1 “511816 "480337 | soso 12° 5
A i 14 +000551| 14 551186 | 64 2°519708 | rao 29°399772
Ea | 16 000591 | 15 “590556 | 65 2°559078| Be
E F| | 16 --000630| 16 629997 | 66 B598hi9} ato 0282
2s | - 17 -000669 | 17 “669297 | 67 2-637819 | rao Pat OO
lz = 18 -000709| 18 708668 | 68 2-677189] Too bay: 85
=a 19 -000748| 19 -748038 | 69 2°716560 | som hedena
[Fs 20 "000787 | 20 em) +787409| 70 Tem.) 2-755930]} Fyn | pein
=m 21 -000827| 21 “826779 | ‘71 2:795301| #8" ggg
E z| | 22 -000866| 22 “866150 | 72 2-834671; 33° Pibiessi
E sian 23° -000906 | 23 905520 | 73 2°874042| =i - 084666 -
Fat] |, 24 -000945| 24 “944890 | 74 2°913412] 21" -101599
| | - 25 -000984! 25 -984261| 75 2-952782] J -196999
=F | 26 -001024| 26 1:023631| '76 2:992153| 53" 169332
a 27 -001063) 27 1°063002| 77 3°031523| 13° — -953998
== 28 -001102/ 28 1:102372| 78 3°070894 | 2" 507995
Ey 29 -001142| 29 1141743} 79 3110264] 2 1.015991
f Es |) 80 001181 | 80 Sem,)1°181113 | 80 em.) 3°149635 as. 1°269989
i =| baba a 31 001220 81 1:220483| 81 8:189005 | yy 1587486
= il “001260 | 32 1:259854 | 82 B:298875: | ae. 1"
5 = 5 |) - 83 -001299| 33 1-299224| 88 3267746 | ve 2116648
AB 34. -001339| 34 1°338595 | 84 3°307116 |. vo . 2°539977.
IBRL | | 85 001878 | 35 1-377965 | 85 3°346487 | a > 8174972
aH _ || 86 -001417; 36° ~—:1-417336 | 86 3°385857 | 3 £°283295
E ay 37 -001457! 37 1456706 | 87 3*425228} r% 4°'762407—
= | 38 -001496 | 88 1°496076 | 88 3°464598 |. & 5°079954 —
fe =! 39 +001535 | 39 1:535447 | 89 3°503068} 4 6349943.
; es 40 ‘001575 | 40 (4cm.)1°574817| 90 (9 em.), 3:543339] as Led ogi
| A 41 -001614| 41 1-614188| 91 3582709 | * cm
al: 4 42 +001654| 42 1:653558| 92 3:622080] 2 1-111240
| Be 43 -001693 | 43 © 1:692929 |, 93 - 3-661450] 2. 1269989
als ia 44 +001732| 44 1-732299| 94 — — 8*700820]° 9 1 -499787_
wee | 45 -001772| 45 1:771669 | 95 3°740191 |g 1587486.
af 1B . 46 ‘001811| 46 1°811040| 96 B°779561) 44 -1+746234
rer = §| - 47 +001850| 47° 1°850410.| 97 -8°818932 RY 1°904983
mal: - 48 -001890 | 48 1°889781| 98 3858302} ay -9-068732 ~
mule = 49 -001929! 49 ites 99 3897673] 2 2-222480 —
| BBE 50 -001969 | 50 (5 cm.) 1+968522 | 100 (10 cm.=1 decim.) }# | 2°381229 |
maiz: 60 -002362 1B) 2:589977:
4 E 4 70 *+002756 decim, ins, 2 5079054 |;
1 TER 80 003150 1 3°937048 eSB UNG beige
: [ee 90 -+003543 2 7° 874086 4 1°015991
| EAH 100 = -(03937 3 11°811130 yd 1°269989
Fe yee Beret 4 15°748178 6 1°523986
5 s | 300 » 011811 5 19°685216 q 1°777984
tales 400 +015748 6 28'622259 8. '2-031982
Ai 5600 “019685 7 27° 559302 9 2°285979
| 600 +023622 8 31496346 - 10. 2539977
pe ae | 700 1027559 9 85 °483389 11 2°793975
(10mm,=1em || 800 -031496 10 (1 metre) 39°870432 1ft 3047973
10 cm. =1 dm. : 900 * 035483, | , = 3° 280869 ft. ‘ yea al
0 ass. se. 1000 (=1 mm.) | Oa = 1093623 yds. lyd.= +914392
< J
Py
4
(8):
JOURNAL
OF THE
ROYAL MICROSCOPICAL SOCIETY,
Containing its Crangacttions and Procecbings,
AND A SUMMARY OF CURRENT RESEARCHES RELATING TO
ZOOLOGY AND BOTANY
(principally Invertebrata and Cryptogamia),
MICROSOOPY, &c.
Edited by —
Frank Crisp, LL.B., B.A.,
one of the Secretaries of the Society and a Vics President and Treasurer of the :
Linnean Society of London ;
WITH THE @ ASSISTANCE OF THE PUBLICATION COMMITTEE AND
A. W.’BenneEtt, M.A., B.Se., FE. Jerrrey Betz, M.A., Rs
Lecturer on Botany at St. Thomas’s Hospital, |’ Professor of Comparative Anatomy in King’ 3 College,
S. O. Rintzy, M.A., of the British Museum, Jouw Maya, Jun.,
‘and Frank E. Brppagp, M.A.
_ BELLOWS OF THE SOCIETY. ~
THs Journal is published bi-monthly, on the second Wednesday of hs
months of February, April, June, August, October, and December. It ©
varies in size, according to convenience, but does not contain less than
- 9 sheets (144 pp.) with Plates and Woodcuts as cae The peice? 1029) 2:
non-Fellows i is 5s. per Number.
The Journal comprises :.
(1.) The TRANSACTIONS pad the ProcnEpines of the Societys
- being the Papers read and Reports of the business iene
acted at the Meetings of the Society, including any-
observations or discussions .on the- subjects Reonerey
forward. .
eo Summary of CuRRENT RESEARCHES relating to Zooey
and Botany (principally Invertebrata and Cryptogamia, — ae
with the Embryology and Histology of the higher Animals
~. and Plants), and Microscopy (properly.so called): being ©
abstracts of or extracts from the more important of. the
articles relating to the above subjects contained in the
- -yarious British ‘and Foreign Journals, aw os oe ig
from time to time added to the Library. fe
cations of Papers printed in the Transactions are Sotitled to 20 copies -
- of their communications gratis. Extra copies can be had at the price he
. 12s. 6d. per half-sheet of 8 pages, or less, including cover, for’a mimimum —
- number of 100 copies, and 6s. per 100 plates, if plain. pe lec by
ae P.O.0. is requested.
"All communications as to the Bf saa should ‘be addressed to the fe zi
Editor, payed pa: Society, —s 8 eles: Strand, W.0.
| Published for the Society by
WILLIAMS AND NORGATE, ate
LONDON AND EDINBURGH. = : Set ; i “S : Hares
(e294)
| Lgaaee aS peers SOCIETY’S TRANSACTIONS (3 vols., half-
calf) ; QUARTERLY JOURNAL OF MicroscoproaL Sorence (16 vols.,
half-moroceo) ; and Montniy Microscorican Journau (18 yols., half-
ealf) for SALE. Price £20.
Apply to Mr. J. Wzsr, at the Dosteny’s Library.
ROYAL MICROSCOPICAL SOCIETY.
MEETINGS FOR 1884, at 8 p.m.
Wednesday, January .. .. 9 | Wednesday, May ..~.. .. 14
% Fersrvary... 9.. 18 ‘4 PUNN ok wae ce POE
(Annual Meeting for Election of i OcropeR .. .. 8
Officers and Council.)
si Novemprr.. .. 12
ms Marca Sek Agha
Bs DrcempBrr .. -.. 10
e BEBE AS vie ie 9 :
THE “SOCIETY”? STANDARD SCREW.
The Council have made arrangements for a further supply of Gauges —
and Screw-tools for the “ Soorety ” Sranparp Sorew for OssEorIvEs.
The price of the set (consisting of Gauge and pair of Sani eoolay te
128. 6d. (post free 12s. 10d.). Applications for sets should be made to Pane .
Assistant-Secretary.
For an explanation of the intended use of the gauge, see Journal of the
Society, I. (1881) pp. 548-9,
ADVERTISEMENTS FOR THE JOURNAL.
ee.
Mr. Cuan.es Buzncows, of 75, Chancery Lane, W.C., is the authorized
' Agent and Collector for Advertising Accounts on behalf of the Society.
(7 10.)
CHARLES CORPO,
LATE MANUFACTURER
PARTNER WITH OF
Rd. BECK, - SCIENTIFIC.
ae ( INSTRUMENTS.
PATHOLOGICAL = : :
Pee ee, i ie
- PHYSIOLOGICAL oO Gor
PREPARATIONS. Students and
_ STAINING FLUIDS Amateurs.
AND ALL
ACCESSORIES
FOR STUDENTS
~ ILLUSTRATED
CATA cs ae
~{00,NEW BOND STREET, :
- LONDON, Wa
| N.B, ‘SPECTACLES!! se
3 _ooUUisTs PRESCRIPTIONS RECEIVE PERSONAL ATTENTION s
| AGENT FoR W. H. BULLOCH, CHICAGO, ILLS.,’ U.S.A, FAR ye
R. H. SPENCER & GO., N.Y., U.S.A.”
JAMES L. PEASE, MASS., U.S.A.
M. PRAZMOWSKI, PARIS.
M. A. NACHET, PARIS.
: ero Goren
el[MoOTACN RF Vitae nuUutd Cae Jo OTe wt IE
“duat 29 2 WeUrMeyy 4aseMy i
AU
200 “i
F29 9ALVDOG OOOCSM@OSa0gq 2066 acd 000 0@ 0a0 0008 0099099 OF
“89 ODBOSGOSGOES06099008 900 2006 @OC 08259 Dav qoaesOI7E2!
2°900G ° Oe SOSSGSCOGOOGOOPS
se0C96CG000G5808 aa th eo Qos 7) Py
2 8O9G909099000000 Beg 32.25 0000080998 09ae0
20008 Qogooe : om
SOG 0090 2820ecGqgo08 SeaQc 4 pains geoseesesens = a
260 ¢ 2008 eoee
LLIVIOSSOSGOOOS OG G S Geoe tl 800g * Sacccousseen echoes ea
re > °° @ een a: &
2 Oy
—
Sas AG eee
‘or euesce
Ray ie
6 ~ RES. GO OOO yee
Res i SSiecseess
WA Id AL TOA Tl was 00S SOlN et NeEnoOr
JOURN. R.MICR. SOC. SER... VOL. PL IX.
J.H.L. Pls gel del. West, Newman & C2 Jith.
Surirella Triceratium & Coscinodiscus.
JAIN VY Avy
JOURNAL
OF THE
ROYAL MICROSCOPICAL SOCIETY.
AUGUST 1884.
~ = =
iQ ‘ww [T) |
~~ tone) i
a
=
TRANSACTIONS OF THE SOCIETY.
XI.—Researches on the Structure of the Cell-walls of Diatoms.*
By Dr. J. H. L. Fugen,
(Read 12th December, 1883.)
Puates VIII. anp IX,
THE various objections made to my previous researches have induced
me to undertake a re-investigation, and although this has for the
most part been simply corroborative, it has appeared to me desirable
to publish the results, together with some obtained in reference to
other diatoms of which only preliminary communications (7) have
hitherto been published. .
Day by day the old erroneous views on the structure of diatoms
are repeated in the text-books of Botany, and nobody seems to have
approached the subject seriously ; the present paper may therefore,
I hope, arouse sufficient interest to induce further investigation.
I. Meruop or INVESTIGATION.
I have already (6) described the methods which I have followed
in the investigation of Pleurosigma ; but it is necessary to refer
here to the method of section-cutting. In applying my greater
experience to Plewrosigma and other diatoms I have obtained
generally much better results than formerly, which have lent addi-
tional confirmation to my paper of 1870.
Time of making Sections.—Accidentally I made my original
investigations during the summer. When in the winter I wanted
to replace some preparations, I found it impossible to obtain success-
ful results. ‘The cause was the artificially heated room. It is
useless to attempt to bring the gum to the right degree of hardness
by the addition of glycerin, sugar, &c., as, in consequence of the
* The original paper is written in German, and has been translated by
Mr. J. Mayall, jun,
Ser, 2.—Von, IV. 2M
506 Transactions of the Society.
proximity of the face and the hands, the aqueous contents of such
strongly hygroscopic substances are subject to an uncontrollable
change, so that we must work with pure gum arabic and in the
summer.
Slight differences are caused by the weather or by the position
of the sun. Sections of the coarser diatoms which are not required
to be of extreme thinness are best made with a clouded sky or in
rainy weather. Sections of Plewrosigma succeed best when the sun
shines directly into the laboratory without striking upon the Micro-
scope. I can hardly too strongly dwell upon the necessity of
entering upon such experimental investigations under the best
physical conditions, absence of vibration, noise, &c. :
Placing the Frustule.—By my earlier method sections in
different directions were obtained hap-hazard because the frustules
were lying pell-mell in the gum. I have now improved the method
as follows :—I take a number of frustules like a bundle of rods and
cut sections in the exact transverse or longitudinal direction. With
this important but difficult method every one must become familiar
if he intends to check the results (hereafter described) which I
obtained with Pinnularia.
(1) If we wish to examine uninjured specimens, the diatoms are
first stained, usually by picro-carmine; they are then put in absolute
alcohol. A glass slip is coated with collodion, and allowed to set.
To avoid peeling when dry, the collodion must not be too thick. A
drop of thick gum is then put on. A cluster of diatoms is taken
direct from the alcohol with forceps and placed. in the gum. In
consequence of the current set up, the diatoms immediately distribute
themselves equally through the gum. As soon as the edge of the
gum begins to harden, one frustule after the other is drawn to the
edge by a very fine needle, where, with proper manipulation, they
can be piled up like a bundle of rods. All those which interfere with
this piling up should be removed. Owing to the staining, the
frustules can be readily seen on the transparent ground. As soon
as the edge dries, a drop of fluid gum is added by a needle, and this
process is repeated until the solid layer of gum has reached such a
thickness that a displacement of the frustules need be no longer
feared ; a small patch of collodion is then put on. The preparation
is now cut out by four cross-cuts and carefully removed from the
glass ; the bundle of diatoms in gum being contained between two
films of collodion. It is advisable to make a drawing with a high
power to show the position of the individual frustules and aid in
the identification of the sections. The preparation is then put
upon a nearly dry flat drop of gum on a piece of cardboard, and the
base and the edges are made to adhere, if necessary, by a few drops
of water, and by the addition of minute drops of gum it is so im-
bedded that at last it is entirely surrounded. This must be carried
The Structure of Diatoms. By Dr. J. H. L. Flégel. 507
out so cautiously that the collodion films do not separate; very
careful watching of the imbedding process is therefore necessary,
especially also to avoid cracks which commence at the edge and
might easily extend to the object. From this bundle, sections may
be made according to the method described by me in 1870.
(2) Any one wishing to study the structure of the individual
valves and mark their manner of combination can shorten this
somewhat detailed process. A cluster of diatom valves is taken
out of the alcohol and placed in a large drop of water on a slide ;
and the water is allowed to evaporate after the valves have been
evenly distributed. A drop of gum already dry—if possible with
a flat surface on a piece of cardboard—should be in readiness ;
another piece of glass is coated with oil of turpentine, which is
allowed to run off so that a very thin film is left, which does not
readily dry. In this the point of a fine needle is dipped vertically,
taking up sufficient oil so that by touching a frustule lying on
another slide it will adhere. Thus the frustule can be put on
the hardened drop of gum which has been moistened by the breath ;
this is repeated with a number of valves ad libitum, and finally
they are covered with minute drops of gum till the required
thickness is attained. This transference of dry frustules upon
the dry gum is much easier than the process with fluid gum
described under (1), because, with the latter, it frequently occurs
that in bringing a new frustule into place the others are disturbed.
With uninjured frustules process (2) is not available, because
these, after the drying of the thin upper layer of gum moistened
with the breath, will at once become charged with air and baffle
any cutting. This absorption of air can only be avoided by trans-
ferring the frustules from the alcohol directly into the fluid gum,
which then diffuses equally through them. At the most the
frustule at the moment of hardening is slightly compressed, which
injures somewhat the appearance of the sections.
Making Sections.—Numerous attempts to cut diatoms on the
microtome failed, and I always returned to cutting by hand, under
a dissecting Microscope. Gum is not favourable as the imbedding
medium for the microtome. If a better medium were discovered
(paraffin is useless), then a new era would open for these researches.
Knives with broad backs should be employed; the angles of
inclination to the cutting edge I have used are 21° 20’.
Piling-up of the Sections.—Ptitzer (19, p. 42) formerly pro-
posed to moisten by the breath the gum-chips containing the
diatom sections after they had been put upon the slide, whereby
they naturally adhered. Anything more unpractical cannot be
imagined; the very thing one wishes to avoid—namely, the dis-
turbance of the sections—is by his method certain to occur, and in
the most favourable case we have a hardened drop of gum in
2M 2
508 Transactions of the Society.
which are scattered all sorts of fragments of the diatom sections,
which the observer may be able to define with reference to their
previous position, but which are utterly useless for the study of real
details of structure. The unavoidable proximity of finger and
face during the cutting is injurious, because the immediate sur-
rounding atmosphere of the operator always contains a quantity
of moisture which causes the delicate chips of gum immediately
to adhere. In piling-up the sections we should most carefully
avoid every increase of moisture, and during the operation
the breathing should be suppressed. If after discharging the
sections from the knife we do not intend to put on the cover-glass
at once, then the slide with the chips should only be lifted up when
in sunlight and under protection from dust. As a rule, time
should not here be lost. It is advisable before putting on the
coyer-glass to touch two corners, which first come in contact with
the slide, with small drops of balsam, so that during the lowering
of the cover-glass it does not slip out of place and so grind up the
very brittle chips of gum. The lowering of the cover-glass should
be done slowly and steadily. If let fall, the puff of air will blow
away the chips. If the chips, on account of too little moisture in
the atmosphere, are curled up, the cover-glass will flatten them
out, the gum on the edges may split, but the centre becomes
flat_and is often very useful. In general, however, it is recom-
mended, on the days when these difficulties occur, to postpone the
operation. Once for all, I state that flat sections are always the
most instructive. After putting on the cover-glass a proportion-
ately small drop of thin fluid-balsam is added on the edge—only so
much that the sections are imbedded in it. After a few days the
vacant spaces are filled up by fresh drops of balsam ; a derangement
of the previously filled-up sections is no longer to be feared.
Series Preparations.—With Pinnularia the making of: series
sections is almost a necessity, especially for the longitudinal sections,
My procedure is as follows, though I am well aware it is capable
of improvement. I cut off No. 1, leaving it on the edge of the
razor ; then I take a second section a little further off, and so
on, until five are on the edge. These I transfer to the slide
with a needle, and as nearly as possible in a straight line. This
is repeated with the other five sections which form the second
line. Then I take a new slide, and thus get decades of sections
from a bundle previously prepared. A disadvantage is that some-
times the sections do not remain on the edge; by falling upon the
table they are lost. Also that not seldom one cuts a gum-chip
as a numbered section, which on further examination proves never
to have touched the bundle of frustules. By disregarding these
very troublesome mishaps, the series-section method according to
my view gives the most beautiful results obtainable with such
The Structure of Diatoms. By Dr. J. H. L. Flogel. 509
delicate objects. As an example, I may mention a bundle of
P. balticum in my possession in 150 sections, of which 100 were
successful; of these about 70 could be identified as being from one
frustule.
Preservation of Preparations.—This subject is unfortunately
for me at the present moment one of the most troublesome. One
would anticipate that by taking quite dry gum imbedded in balsam
slowly hardened, the preparation would be almost indestructible.
I regret to say this is not always the case. My preparations
of 1869 remained stable six to seyen years. But afterwards
a fatal change took place with many. The sharp straight edges
of the gum-chips lost their sharpness, the edges rounded off, and
lastly a kind of oil-drop took their place, in which the former
beautiful sections almost disappeared. Whether my present house
is too damp, or whether moisture works through the balsam along
the glass up to the sections, I do not know; but I suspect some-
thing of the kind. The serials I made last June and July have
kept in partibus well up to the present, but a portion commenced
in October to change, although as a protection I had covered the
edges with asphalt and kept them in a room which was warmed
every day. ‘The real cause of the destruction of these preparations
is still a mystery, and I would recommend that sections should
be studied immediately after being made.
II. Resvuuts oF THE INVESTIGATIONS.
My first paper was confined to the varieties of Plewrostgma, and
I now give an account of all the other diatoms the structural details
of which I have investigated. I may at once say that a general
sketch of diatom sculpture cannot be given. We cannot take the
structure discovered by me in Plewrosigma (consisting of chamber-
like holes in the interior of the cell-membrane) and thus explain the
structure of all diatoms, nor can we conclude from Moller’s proved
structure of Triceratiwm (viz. chambers open externally) that this is
the same, mutatis mutandis, with all others of this numerous order.
1. Pinnularia.
Probably the cellular envelope of a great number of diatoms
follows the type of Pinnularia, which may therefore be put first, all
the more so since the views regarding their structure (chiefly based
on Pfitzer) adopted in most text-books, are totally erroneous.
Moreover, the structure of their cell-walls is very remarkable. For
my material (Pinnularia major) I have again to thank Herr J.
D. Moller. It consisted principally of isolated valves which were
510 Transactions of the Society.
treated by different methods, viz. (1) by the section method, (2)
the cast method, (3) the staining method.
§ 1. I commence with the section method, remarking that most
of my sections were made as described under (2). It is requisite
that investigators should keep strictly to this method, otherwise
they will not see the details of structure here described, or they will
obtain from oblique sections images very difficult to interpret. We
require very thin (e.g. 1/1000 mm.),* exactly transverse and longi-
tudinal sections, whilst with Plewrosigma it does not matter if the
direction of the cut deviates more or less from a right angle to the
midrib. The transverse section of a valve of Pinnularia, if it has
not touched the central nodule, has either the form of fig. 1 or fig. 2,
plate VIII., except that in close proximity to the two ends the general
form, by the disappearance of the rounded-off right angle, becomes
semi-circular or semi-elliptical. In order to elucidate the change in
the appearance of the mner structure we must remember that
the surface image of Pinnularia exhibits coarse transverse striz,
ending near the midrib, and which are regarded by Pfitzer and
others as superficial furrows, and they have therefore been designated
by various improper terms, such as furrows, surface sculpture, &c. In
reality the outer surface, independently of the midrib, has neither
elevations nor depressions, but is quite plane. If the section passes
through the middle of a so-called furrow, it appears as in fig. 1 ;
if it passes through the interspace, then it appears asin fig.2. The
separate parts of the image are, as will be shown later on, to be
explained as follows :—Hach so-called furrow is an inner chamber
of the membrane, and, in proportion to the chambers of Plewrosigma,
of enormous size, since it extends from the edge of the frustule to
very near the midrib. Itis also of almost equal thickness through-
out. But what is most remarkable is the fact that each chamber
has a rather broad opening on the inner side of the cell-wall, by
which it can be readily examined. The outlines of the opening are
easily observed in the surface view, and have been often represented
in the better class of illustrations (vide Pfitzer, 19, pl. 1, fig. 2).
The draughtsmen, however, do not seem to have had a clear con-
ception of the signification of these lines. Pinnularia is represented
as a definite proof that the cell-envelope is broken through in the
midrib, thereby allowing free exit to the protoplasm. All former
reliable researches having apparently proved the non-existence of
openings, and the endosmotic process having been generally accepted
as the cause of movement (vide Naegeli, Von Siebold, W. Smith,
Rabenhorst), Prof. Max Schultze (24) in 1865 put forward the
opposite view and considered it proved that at the raphe of the
* Sections as made by Pfitzer (19, p. 43) which are twice or thrice the thick-
ness of a furrow, cannot, as a matter of course, be used for a delicate observation.
At the best one recognizes only the general outline.
The Structure of Diatoms. By Dr. J. H. L. Flégel. 511
diatoms there was a glutinous organic substance which could only
be protoplasm. In 1870, Prof. Dippel’s work (3) appeared refuting
Schultze’s view, and drawing attention to the fact that the mid-
rib is not a cleft but rather a thickened line, having on the sides
narrow longitudinal strie without perforations.* Then came
Pfitzer’s work (19), who discovered the long-searched-for cleft and
represented it so well that its existence is no longer doubted. He
declares the detection of this cleft to be a task to be solved only
with the highest powers, and draws a figure of a very narrow
V-shaped opening through the thick envelope. Under existing
circumstances it was of great interest to test Pfitzer’s statements.
The conclusion I came to was to agree entirely, without reserve,
with Dippel, and I must therefore deny the perforation of the
cell-wall. This result cannot, however, be easily obtained. The
number of more or less good transverse sections of Pinnularia
I have is about 600; in most of them I actually observed in the
midrib a fine transverse cleft. Its direction and its fineness are
shown in figs. 1-3. They can be well seen with 300-400 where
the section is good. With regard to direction I rarely see the
cleft so V-shaped as drawn by Pfitzer; on the contrary, in most
instances it commences on the outer surface at right angles to it.
Then arise a great variety of changes in the appearance. We
meet with sections in which it goes straight to the inner surface ;
others where the vertical portion has a small hook turned
inwards ; again, others where the portion facing the inner surface
is obtuse to the vertical,—this case (not at all uncommon) is repre-
sented in fig. 3. Such a change may be explained by a real
difference in the object, which Schumann also quite correctly found
with the surface view (23, p.73). A careful comparison of a great
number of transverse sections, made according to method 2, will
show in most cases the cleft going up to the inner side of the
membrane. The question remains very doubtful whether the base
is closed by a very thin envelope. After having made collodion
casts, the image of the outer surface could be easily inter-
preted; the fine cleft became filled with collodion, and in harden-
ing a distinct midrib remains, almost exactly the same image as
we see in the surface view. But the inner surface remained quite
obscure. If a perforation of the membrane really exists, a similar
midrib should be seen; but this is not the case. I have made
a considerable number of such impressions, and not the slightest
trace of a midrib could be seen, even with oblique light.
These impressions fully convinced me that the fine cleft was
closed at the base. That the transverse sections mostly show a
fully developed perforation may be attributed to the following
* This is what I proved simultaneously with Pleurosiyma (strie without
spores).
512 Transactions of the Society.
cause :—In transferring a frustule to the gum it may, of course,
be done according to method 2 without injury, but not always.
In further experimenting the mass, in hardening, may suffer un-
equal pressure on the valves, causing them to break, as also stated
by Pfitzer (19, p. 50), and this is very likely to occur in the mid-
rib. In this case they were injured before cutting. It is, how-
ever, more probable that injury occurs during the cutting. The
entire thickness of the silicified membrane adjoining the midrib
is about 8-10 times as large as that of the fine envelope. As soon
as the knife presses against this solid mass, the cap easily breaks
off, which appearance is also observed with thicker masses at the
central nodule crumbling out. In order to clear up this point I have
made another series of sections according to method 1, in which
injuries are more avoided. The best thereof show unmistakably
at the base of the furrow this fine capping envelope exactly as
represented in figs. 1-3. If the transverse section goes through
the central nodule, the image then becomes as in fig. 4. Hence
the nodule is also here a strong thickening of the midrib inwards ;
outwards it has no distinction beyond that the middle line is
broken and does not appear in the transverse section of the cleft.
The membrane is flat. Here it should be noted that Schumann
(23, p. 74) observed two focal images of this nodule in Pinnularia
lata. Ihave seen them oftener in Pinnularia major. But they
do not arise through a channel, as supposed by Schumann, but are
produced by a depression in the centre of the nodule. This may
often be seen without difficulty in a side view of the entire frustule.
Similarly, the end nodules are inward projections.
I will now proceed to the description of the longitudinal sec-
tions. Their appearance must of necessity differ, depending upon
whether the section goes through the openings of the chambers,
or near the midrib, or near the edge of the frustule. Fig. 5 repre-
sents a section through the chamber-openings showing the siliceous
membrane with numerous long pegs projecting inwards in the
frustule; these are the vertical partition-walls of the chambers.
In fig. 6 we have a median longitudinal section ; the chamber-
spaces appear like beautiful squares slightly rounded off in the wall-
substance. The longitudinal section taken from the chamber-
opening towards the edge shows hardly any difference from that
last described. A vertical section along the midrib and through
the central nodule has hardly any importance. If a longitudinal
section goes a little obliquely towards the midrib, it shows in
places the image in fig. 5, and in other places that of fig. 6.
in all cages the outer limit of the cell-wall is perfectly straight
throughout; nothing in the outline suggests furrows on the surface.
From this representation it may well be supposed that transverse
as well as longitudinal sections of Pinnularia are vexatious prepa-
The Structure of Diatoms. By Dr. J. H. L. Flégel. 5138
rations in the hands of the tyro. In one and the same section he
observes the most beautiful closed chambers and is fully convinced
that my description of the Plewrosigma chambers is accurate. A
few micro-millimetres further on he notices the magnificent pro-
jections of the wall, not inferior to those of the epidermis or the
vessels of higher plants, and with this he proves that I have erred
in all points. If he follows Pfitzer’s advice with regard to breathing
on the sections and thence obtains a mass of fragments, he will know
neither what is outside nor what is inside the valve. For instance,
if he turns round fig. 5 he will then see, according to his taste and
intelligence, Pfitzer’s furrows on the outer surface, and then he
confirms all Pfitzer’s fairy-tale. ‘Therefore I admonish every one
to use the utmost precaution in interpreting the images !
§ 2. Collodion Casts.—For the technical process I refer to my
former essay (6, pp. 489-90). These casts are of much greater
importance with Pinnularia than with Pleurosigma; I can there-
fore seriously recommend sceptics to try my experiments. The
method is so easy in practice that even inexperienced manipulators,
unable to do the cutting, will in this way obtain a general view of
the details. It has been already observed that the chambers can
be injected from the opening, so that in pouring fluid collodion on
the inner side of the valves, it enters the opening and fills the
chambers. With the evaporation of the ether the mass contracts,
and after the collodion has hardened one sees the contents of the
long cylindrical chamber shrivelled-up to a thread. The image
takes the shape of the letter T. The vertical line is the collodion
filling up the chamber-opening ; the horizontal is the collodion
which fills the space of the chamber. If, therefore, the Pinnularia
valve is taken away from the cast, these small T’s stand in military
order in lines parallel to the midrib on the film. This T is
mostly so elastic that without breaking it can be pulled out of the
chamber.
Fig. 7 is intended to bring clearly before the mind in a diagram-
matic form what I have described above for a small portion of the
cast; it is impossible to draw it exactly, because the interpretation
chiefly depends on the alteration of the focus. With the lowering
of the tube the horizontal T threads appear before the surface of
the envelope is seen, and they disappear when the latter becomes
visible. It is, of course, desirable always to examine for oneself such
a cast. The central nodule leaves behind a pretty bold depression
of elliptic shape. Sometimes are seen two small flat cavities
adjoining each other, which also indicate the depression in the centre
of the nodule (as above stated). Except the broken line in the
middle, the collodion cast of the outer surface of a valve shows only
a perfectly plane surface; but this line increases in distinctness
near the central nodule and ends with a thickened point. This fact
514 Transactions of the Society.
implies that the cleft furrow is very deep, a fact which is also con-
firmed by the transverse sections. This is simply the consequence
of the gradual increase in thickness of the entire membrane, whilst
the closing envelope is probably of even thickness. Closer obser-
vation will show that the surface is not everywhere alike ; the area
along the midrib, i. e. the portion free from chambers, appears quite
plane ; the other, on the contrary, a little granulated, and occasion-
ally one can even see a kind of glitter of chambers. In this case the
cast teaches more than the longitudinal section, since it seems to
display an unusually fine surface-difference which is not brought to
the eye by the longitudinal section. Similar experiments were
made with Pleurosigma. Asa matter of course, this condition of
surface has nothing to do with transverse striz of Pinnularia. I am
still in doubt whether this image is not called forth by the different
evaporation processes above the chambers, therefore perhaps it may
not correspond to any real difference between the valve surfaces.
It is true that where air-bubbles are in the collodion the surface
after hardening looks different from what it does when free of
bubbles.
Thus a complete and exhaustive explanation is given of all
appearances of the surface image of a Pinnularia. In the imbed-
ding of the valves in balsam, chamber and opening are filled with
the strongly refractive substance and thus produce the coarse trans-
verse striz. Hach stria is a chamber.
§3. Staining Processes.—I cannot call these experiments more
than tentative; they were intended, after I had recognized this
most interesting condition of the chambers, to provide preparations
in which the chamber-spaces alone should be filled with colour.
The wall-substance, as is well known, does not take the staining.
The experiments were made with solution of silver, picro-carmine,
and Prussian blue; with the latter substance only I obtained pre-
parations which were partially serviceable. The valves were put
in aqueous solution of Prussian blue, poured off after some time,
immersed in alcohol and constantly shaken to remove the blue
which had deposited in and upon the valves. They were then put
into balsam. In successful instances, not occurring frequently, the
chamber is seen blue in the colourless wall. I have not persevered
with these experiments.
§ 4. Passing on now to the literature on Pinnularia sculpture,
Schumann as far back as 1867 was approximately correct in his
views. In his work (23, p. 73) he says that “in a fragment in
partially reversed position the channels were most raised at the
middle; each channel seems to consist of two vertical walls, the
vault across being open towards the middle line.” On pl. IV.,
fig. 54, B, he exhibits such a fragment, from which one can imagine
what he means. The real state of affairs could not be discovered
The Structure of Diatoms. By Dr. J. H. L. Flogel. 515
by Schumann’s method ; it is therefore unnecessary to enter into
the details of his statements. A considerable retrocession is found
in Pfitzer’s works of 1869 and 1871 (18 and 19). In the former
is briefly indicated that in Pinnularia we had to deal with smooth,
narrow, elliptical spaces, concave outwards (pores = cost, Smith).
In his second he substantiates this view by details. His views
do not require special refutation ; they are wholly wrong.
In my lecture (7) I first gave a correct representation of the
real details, with preparations. It seems a pity that this lecture,
referred to by Pfitzer (1873) in Just’s ‘ Jahresbericht’ (11, p. 28),
did not give him occasion to make once more transverse sections
of Pinnularia, for in all probability he would have been luckier.
The most recent paper, however, which has come to my knowledge
is a notice by Prof. Hallier, April 1882 (10, p. 156), according to
which he holds a similar view with regard to the structure
of the silicified membrane of Cymbella as Pfitzer expounded for
Pinnularia. If this can be looked upon as a confirmation for
Pinnularia, then I do not envy Prof. Pfitzer’s new triumph, which
places Hallier’s reputation in an unfavourable light.
Among the supporters of this unfortunate furrow-hypothesis
seems to be Borscow, whose work I have not seen (vide Pfitzer,
Just’s ‘ Jahresb.,’ 1873, p. 28).
The literature as to the supposed perforation of the cell-wall
along the middle line has been given above. I need only add
that Pfitzer (19, pp. 175-80) has tried to dispose of Dippel’s
objections to Schultze, and seems to have succeeded tolerably well
in his so-called proof of the longitudinal cleft. But when he states
that, in explaining the apparent movements, Dippel has put by far
too great weight on the endosmotic processes, this objection falls
to the ground, since Prof. Engelmann (4) has discovered a means
in Bacteria to demonstrate the development of oxygen by diatoms
under the Microscope, thereby furnishing the proof that the unseen
gas-molecules escaping from the cell cause movement. Be this
attraction or not of the Bacteria, these currents of gas, like enter-
ing or flowing currents of water, must have such force that they
can carry away a detached cell.
2. Navieula.
Of the numerous species, I have only examined the coarser
striped Navicula lyra, Ehrb. The material was obtained from
the mud gathered during the expedition of the “ Pomerania” (9). I
chose a serial slide, on which were placed twenty-seven transverse
sections through one valve. The lengths of the first and last sec-
tions led me to anepone that three or four sections had already been
made from the valve at either end, and by mischance are not on
516 Transactions of the Society.
the slide; consequently the sections are not all perfect, for a
medium-size valve often contains more than sixty rows of dots. Be
this as it may, several sections are excellent. From this I infer
that the “lyra” figure is produced by thickened and chamberless
portions of the cell-wall. In lke manner, the central nodule is a
large flat thickening of the wall. Fig. 9 probably shows the sec-
tion exactly through the middle of the valve (No. 13 of the series) ;
fig. 10 section not far from the middle (No. 17 of the series) ;
fig. 11 section not far from the end (No. 1 of the series). In the
two last we see the thickenings, which I have designated as “ lyra
plates,” clearly project inwards. The sculpture of the dotted portion
of the valve may really be regarded as similar to Plewrosigma ;
but here are clear rows of isolated chambers closed all round.
Towards the edge the valves become thinner and the chambers
smaller. The midrib with the chambers adjacent to it can only
be seen faintly on most sections, especially the projection inwards
is seldom distinct, and in the first section, fig. 11, is not seen.
Longitudinal sections were not made; they probably would illus-
trate the details more beautifully. Combiming with these results
the surface view of a valve, fig. 12, we arrive at the conclusion
that the doubts I formerly entertained (6, pp. 482-4) with regard
to the existence of closed chambers, and of double membranes
connected by column-like supports, are unfounded. The clearly
separated spherules of the surface image also show separated
chambers, and this is equally true of the entire series of rows.
The space between such rows of dots, which is not rarely twice the
breadth of the chamber diameter, represents without doubt the
solid wall, which has not suffered a visible separation ; hence there
is no communication between the separate rows. If we have thus
before us the connecting link to Plewrosigma, it only requires
another step to arrive at Pennularia: if the chambers forming one
row are brought together a little closer and coalesce with each
other, then we get the extended cylindrical chamber of the former.
It is true that the large opening is unconnected.
3. Plewrosigma.
§ 1. Addenda to my former researches.—I add a few recently
obtained results, chiefly due to the method subsequently learnt of
placing the frustules in position and making serial sections (vide
supra, “ Method of Investigation,” (1).
(1) I was formerly obliged to neglect the transverse section of
the central nodule (6, p. 478), because I could not find it; but in
serial preparations of P. balticwm as well as P. angulatum, cut
exactly transversely through a bundle, there is no difficulty in
The Structure of Diatoms. By Dr. J. H. L. Flogel. 517
detecting it. In order to remain quite objective on this point with
regard to the sculpture of Plewrosigma in general, I have made
photographs of a number of transverse sections, and amongst these
one of a central nodule of P. balticwm (French specimen, 6, p. 480).
This shows without doubt that, as already proved by the cast
process, the nodule is a solid thickening of the wall projecting
inwards.
(2) The Girdle-band was formerly described by me (6, p. 480,
figs. 11 and 13) as a simple membrane. Pfitzer refuted this
correctly (19, p. 20). In my present sections made exactly
transverse to the median line, I see it sometimes single and some-
times double, probably due to the close proximity of the two plates.
If I gave no figures of this formerly, the reason was that in cases
where it appeared double I concluded that accidentally with the
imbedding in gum foreign matter adhered there, a supposition
which might be excused by the fact of using only sections made
through frustules lying pell-mell.
(3) What I termed with P. baltiewm accessory rib (6, p. 481,
and fig. 13), namely, a small second rib-like edge on the one side
of the real median line, does not change position in all cases. For
example, if it lies on the right of the main rib in one valve it will,
as a rule, be seen in the other valve on the opposite side, that is,
on the left. Exceptionally it may be found in both valves on the
same side. Numerous experiments by crushing Plewrosigma valves
under heavy pressure have taught me that, contrary to the former
(6, p. 484) negative result, we can sometimes find fragments in
which the one membrane is isolated, that is to say, it appears
without any markings because the chamber-walls are rubbed off.
This, however, is only found in a very narrow edge-portion of such
fragments. Which membrane it is—whether the inner or the
outer—cannot be determined as a matter of course. Mistakes with
such fragments of uninjured valves, in which the markings are
indistinct because the chambers are filled up with a glutinous
substance, are avoided by convincing oneself of the much higher
refraction of the valve in this case, whilst the isolated membrane is
seen only very faintly.
§ 2. Investigations by others.—(1) Pfitzer in his essay (19,
p. 174) speaks of the sculpture of the cell-wall of Plewrosigma ;
but since nothing new is mentioned, I refer on this subject to the
General Remarks given in the third part of the present paper.
(2) Miller has also studied the question, I had sent him a
slide of Plewrosigma sections from the same gathering as the
French specimen described in my original paper, and soon after I
received from him two essays (14 and 15). As he was a novice in
section-making who had occupied himself with coarse objects
only, I treated his strange attacks with silence, in the hope
518 Transactions of the Society.
that an able observer would take up the matter and confirm my
work, whereby I should have been relieved of the trouble of
replying. In this hope I have for ten years been disappointed,
and I am obliged now to refute Miller.
T do not know whether Miller has made Plewrosigma sections
according to my method, or whether his statements are made from
examination of my own preparations. He says that my drawings
are incorrect, especially that the diameter of the transverse section
of the walls is proportionately much too thick, whilst the strong
refractive thickenings at the ends of the same are not sufficiently
given, hence he will not admit the existence of closed chambers
(15, p. 621).
With regard to this question, I have to reply that all my
preparations of Plewrosigma were not only submitted to the late
Max Schultze, and every doubtful and difficult point demonstrated
before him by me personally, but that my diagrams were recognized
by him as correct, and by his express desire my paper was com-
municated to his ‘Archiv.’ This I mention without putting high
value on the influence of mere authority. Next I refer to my own
paper: on pp. 82-84 I discuss in considerable detail, with reference
to the coarsely marked P. balticwm, the point as to the existence
of columns between two envelopes or closed chambers. Nobody
will infer from my description and diagram that I meant cylindrical
columns or chamber-walls of equal thickness, nor that I intended
to deny the thickenings at the ends. No such idea was in my
mind. But if such end-thickenings do exist it is an understood
thing that they are of pyramidal shape, the base towards the
membrane, the point towards the space between the membranes,
and they must operate as strong refracting bodies just like small
convex lenses. On p. 511 I illustrate for this purpose the most
striking comparison—the liver-wort leaf with large mesh-work.
Choosing for study sections of a considerable thickness, and in
which therefore two entire chambers might be found lying one
over the other, then the effect is doubled; the two membranes
will be seen more conspicuously projected from the inner space with
the thinner walls. But such sections I did not select for my dia-
grams, it being the rule, whenever the finest structural details were
under investigation, to examine and to draw the thinnest sections
or the extreme margin as the most reliable portion. In examining
such sections one sees the detail exactly as I have represented it,
and I must continue to assert that my diagram is true to nature.
A second point of attack to be disposed of is Miiller’s idea that
his flooding experiments (14, p. 75, and 15, p. 621) could not be
brought into harmony with chambers closed from outside. I put
entirely aside the value of such flooding for the elucidation of
details of diatom structure. That all the fluids named by him
The Structure of Diatoms. By Dr. J. H. L. Flogel. 519
will penetrate the interstitial molecules of thin membranes with the
greatest facility is known to every novice. Were one to suppose
or to search for holes with this experiment we should cancel every
investigation made during a century with regard to endosmose.
This point needs no refutation. I refer to what I said, pp. 487-8,
about the penetration of water into the valves, and it will be the
same with all other fluids. The further deductions by Miller,
pp. 622-5, in connection with his flooding experiments are by far too
obscure for me. Even admitting the facts with regard to Pleuro-
sigma were as Miiller believes, that the chamber had an opening
outwards as with Triceratiwm, there is no reason whatever to
infer that the microscopical surface-image could be altered in air,
balsam, bisulphide of carbon, &c.. The chambers whether elliptical
or spherical in connection with the wall-nodule operate in the
one case as concave lenses, in the other as convex lenses; whether
they have an entrance from outside or not is immaterial. ‘If en-
trances do exist, but which up to the present have not been
observed, I would sooner admit that they lie on the inner side of
the membrane. In support of this statement is the analogy of
Pinnularia and the collodion cast showing a delicate relief-image
of the inner side (6, p. 493).
(8) Miller seems to think (14, p. 76) that we ought to in-
vestigate the real condition of diatom structure indirectly, and
especially the Plewrosigma sculpture, and in illustration he
describes his investigation of Triceratiwm favus. On pp. 79-80
he has no hesitation in applying to Plewrosigma what he found
with Triceratium. This means, in other words, that everything
said by Flogel withi regard to Plewrosigma does not quite agree
with what I (Miller) found out with Triceratiwm, therefore the
former must be wrong !
(4) The fourth point is Miller’s representation of a transverse
section of Plewrosigma (15, fig. 1aand1b). He writes (p. 637)
that he succeeded in finding it amongst numerous sections, and
then he terms it (p. 621, and explanation of fig. on p. 641)
P. scalprum, with a sign of interrogation. What he has repre-
sented there is a fragment of a very thick transverse section of
P. balticwm! I cannot ayoid calling this a prodigious blunder.
For Miiller, after his researches with diatoms, ought to know that
the small delicate P. scalprwm could never furnish such a colossal
transverse section, in whatever direction made. Further, on
p- 488, fig. 19, 1 have described and figured the transverse section
of P. scalprwm, and the fig. is on the same scale as the transverse
section of P. balticwm, fig. 13. A confusion between these two is
utterly impossible,
520 Transactions of the Society.
4, Surirella.
In avery primitive form Rabenhorst, 1864 (22, p. 9, fig. 12 d),
gave a transverse section of Surirella. It is rectangular, with short
straight lines at the corners. The sculpture of the valve was
minutely described by Pfitzer (19, pp. 108-10, pl. I., figs. 8-10,
pl. V.), and the former researches by Smith and Focke were con-
sidered. About the finer sculpture which produces the transverse
and longitudinal striz Pfitzer said nothing. The representation
of the coarser details may serve as a model, and I shall refer to it
frequently. The only species closely examined by me occurs in
fresh water, and I believe it to be S. biseriata, Ehrenb. The
minute drawing on the surface is like the well-known test-object
S. gemma. From a single valve of this species I made a series of
transverse sections, from another a series of longitudinal sections,
and lastly a collodion cast of the inner side of a valve.
The general outline of the valve, best seen from the cast, is
an elongated oval almost like a lancet. In the middle lengthways
is a ridge, on the margins are the wings as described by Pfitzer in
S. calcarata (19, pl. L., figs. 8-9, pl. V., fig. 6). The surface
between the middle line occupying the highest edge of the ridge
and the wings is bent somewhat wave-like. The wings are not
simple membranes, but are double, a fact already established by
Focke and Pfitzer. They are really folds in the cell-wall. Both
membranes adjoin closely in some places; in certain intervening
spaces corresponding to the waves on the surface they are not
close together, but show a tube-like space. All these communica-
tions end in a delicate continuous tube, which forms the tip of the
wing.
‘The diagram of Surirella consists of (1) a midrib without
nodule or any other distinction ; (2) numerous transverse ribs which
extend at pretty regular distances from the midrib towards the
edges ; (3) transverse lines between these ribs and perfectly parallel
to them ; (4) longitudinal lines of extreme delicacy which cut the
transverse lines at right angles. We will now examine the result
of the transverse sections. The transverse section series com-
mences with a section the shape of which suggests that three or
four had been taken before; the last, No. 66, has had at least ten
successors of equal thickness. From these facts we may appreciate
the delicacy and extreme usefulness of thisseries. Fifty times over
these sections substantiate the correctness of Pfitzer’s images. I
have drawn Nos. 2, 9, 39, 40, and 66. Of the longitudinal section
series I draw only the first, pl. IX., fig. 18, and another, fig. 19,
which goes through the middle of one valve, and is the most
instructive, as it shows most distinctly the waves on the sur-
face. My longitudinal section series has not that technical
The Structure of Diatoms. By Dr. J. H. L. Flégel. 521
perfection which distinguishes my transverse sections, although
it shows nearly all one can reasonably expect. Putting trans-
verse and longitudinal sections together, one readily sees that the
former must look a little different when they are cut through the
elevations or when through depressions. Pfitzer has already drawn
attention to this fact, and as far as I can judge he has deduced it
from the optical transverse sections of the raised frustules (p. 109).
The real transverse sections confirm his view. It is not uncommon
that the section is so thick, that lying at the declining edge of a
wave its outlines in the upper part differ from those in the lower.
Figs. 13, 15, and 16 illustrate this by finely drawn lines. These
are differences which occur with the transverse section of the
wings. The section goes either through a place where the mem-
branes holding together the wing lie closely one upon another,
exhibiting the image fig. 14; or else it goes through the inter-
vening space, then the wing looks like a flat-pressed smooth
surface having a lumen in open communication with the cell
(fig. 15). In the former case one observes at the highest margin of
the wing the transverse section of the extremely thin tube above
mentioned. Pfitzer (vide p. 110) has expressed the opinion that along
the entire wing-margin runs a fine cleft, or that there exist a large
number of extremely small openings standing in one line. This
cannot be taken for more than a mere opinion. My transverse
sections in no way corroborate this opinion; on the contrary, they
show these fine marginal tubes closed everywhere outwards. These
details can be best understood by comparing it with the surface view
of the wing, fig. 18. By comparing the figured transverse sections
together it will be seen that the proportion of the size of the
wing to the surface towards the end is different from what it is in the
middle of the valve. We see further that there is a difference in
the curvature of the surface of the valve, about which more further
on. With regard to the finer sculpture, the transverse sections
exhibit the midrib as an irregular thickening; one sees there a.
point. However, the membrane in its whole extent is so extremely
delicate (the measures give 0°4—0°5 yw, even this is too high) that
it becomes very difficult to distinguish differences of thickness.
Transverse ribs are delineated in the longitudinal section (figs. 19
and 20) clearly like small ovals on the crests of the waves, and these
ovals are mostly more pointed whilst the valleys are rounded. I
see the transverse strice in the delicate longitudinal sections as clear
pearl-like punctures, as in fig. 20. No rib-like projection can be .
observed, however, for the shadow permeates the whole mass so
that it must necessarily be caused ina manner similar to Plewrosigma.
The longitudinal strize I could not perceive with the desired clear-
ness in the thinnest transverse sections, not even with oblique
light. Sometimes I observed a kind of glimmer, but nothing
Ser. 2,—Vot. LV. Qn
522 Transactions of the Society.
beyond this. With central light the transverse sections appear
homogeneous, and flat on both sides. In examining the sections
I could not trace differences in the membrane thickness ; nor did I
observe projections or continuations with one exception near the
edge of the valve outside the wing, and this occurs pretty constantly
and may stand in connection with the attachment of the girdle-band.
On this matter I cannot give more definite explanations. If we exa-
mine the cast in view of these facts, the wave shape of the surface is
thereby substantiated ; it follows that the fluid collodion must have
entered into the tube-system of the wings, and in pulling off the
valve there must have been left behind contracted tubes. In
reality, not far from the edge, such protuberances of collodion are
seen at regular intervals. The cast shows absolutely nothing of
the transverse strize however oblique may be the illumination with
which it is examined. From the above we infer, with regard to
the finer sculpture, that midrib and transverse rib are both wall-
thickenings of which the transverse striae have probably been
produced by the cylindrical hollow spaces within the membrane.
Small hollows of these cylinders then suggest an appearance of
longitudinal lines, and the condition is similar to the transition of the
simply striped Pinnularia to the pointed striped Navicula. This
lesser definition remains obscure. For microscopists these investi-
gations about Surirella sculpture are of some importance, since they
explain various peculiarities of S. gemma which may be looked upon
as similar to S. biseriata. At first sight the longitudinal section,
fig. 19, teaches us that it really is no brilliant performance for an
objective when it shows the much-spoken-of longitudinal striz every-
where at the same time. All that is proved is that the objective
possesses the power of showing at the same not only striz which
are within the focus but others which are beyond. This can be
easily obtained with bright sunlight, but with ordinary day-
light an objective should only show clearly either the striz on the
elevations or those on the depressions. Secondly, the transverse
section near the end, fig. 14, establishes the fact that in order to see
both strize at the same time it is best to examine the end portions of
a valve under an obliquity of illumination of 45° to both directions.
Here the surface of the valve is smoother. Altogether Surirella,
on account of its uneven surface, is a very unsatisfactory test-object.
(To be continued.)
XIL.—On a New Microtome.
By C. Hinton Goxipine-Birp.
(Read 14th May, 1884.)
Tue necessity for providing some instrument which offered the
advantages of modern-microtomes and yet was within the reach of
those whose work being of intermittent character did not warrant
their employing the somewhat elaborate instruments that are
found in laboratories, made me originate the instrument shown in
figs. 83 and 84.
The microtome is intended to be held in the hand during use,
and is of two forms—one for ice and salt, the other for ether.
The former (fig. 83) consists of a cylindrical vulcanite chamber
closed at the bottom by a brass screw-lid, and at the top by a
Fig. 83.
i
«ie
-
| +
| A
‘ih
il
]
iN
disk of vulcanite, having in the centre a plate of brass (freezing
plate) 7/8 in. in diameter, and terminating in the chamber by
a rod of brass. A metal cap surmounted by a glass plate and
pierced in the centre to allow the freezing plate to project, screws
over the upper end of the cylinder, the outer surface of which
bears a male screw of hard metal on which the cap turns. As the
cap is turned round a spring catch clicks at given intervals; these
are so arranged that as the cap rotates from left to right each
click shows that it has sunk on to the cylinder 1/1000 in. ; hence
any tissue fixed on the freezing plate projects, at each click,
1/1000 in. through the hole in the glass plate of the cap, and a
2N
524 Transactions of the Society.
razor now passed over the latter cuts off a section of the same
thickness. By turning the cap through half an interval, sections
of half that thickness may be obtained. To fix the specimen it is
only necessary to fill the cylinder with ice and salt, the specimen
being previously prepared in gum, according to the general rule
when freezing is employed as the means of imbedding.
The form in which ether is the freezing agent employed
(fig. 84) differs mainly in the fact, that the lower half of the cylinder
is a chamber for holding the ether, with the two nozzles that give
the necessary jet. The freezing plate, cap, and regulating apparatus
are the same as in the ice and salt machine. Mr. Swift (to whose
skill and ingenuity the details of manufacture are due) has intro-
duced a very ingenious but yet simple means whereby some of the
ether can be saved from the spray ; much must of course escape,
but much also falls back on to the jets again (since the spray is
a vertical one); this portion impinges on to a funnel-shaped
diaphragm, which acts as a lid to the ether chamber, and through
which, by means of a minute opening, it again finds its way back
to the ether chamber.
For those who, like myself, have to work for a large histo-
logical class, there is nothing equal to the Groves-Williams ether
microtome in the laboratory: but for intermittent and home work ~
I believe that the form of instrument that I present to-night,
leaves scarcely anything to be desired in accuracy of work, simplicity,
convenience, and portability.
XUI.—On some Appearances in the Blood of Vertebrated Animals
with reference to the ocewrrence of Bacteria therein.
By G. F. Dowpzswett, M.A., F.R.MS., &e.
(Read 11th June, 1884.)
THE occurrence normally, of micro-organisms in the bloéd and
tissues of healthy animals, has been the subject of many observa-
tions, in some instances with contradictory results. It is, however,
now well established that, both in man and other animals, they
are constantly present in certain situations, not only in the
mouth and lower intestine, but in some cases at least, in the liver
and pancreas; on the other hand it has been shown that in the
blood they are not usually present in a state of health. ‘To deter-
mine this latter point microscopical examination is inadequate, inas-
much as mere negative observations are inconclusive, and the ques-
tion has been decided by physiological experiment, viz. by taking
blood from the heart or vessels, with precautions against contami-
nation, when it is found that it may be preserved indefinitely, free
from septic changes; and even in some instances, as has been
demonstrated in King’s College by Professor Lister, without
coagulation.
In some pathological conditions—in certain infective diseases,
—as is now well known, micro-organisms are found constantly
present in the blood, and in a few cases are shown to constitute the
true contagium, the actual materies morbi. It is possible too, that
in other conditions not yet investigated —as for instance in a tem-
porary access of fever—they may appear here, starting from those
situations in which they are normally present, and again shortly
disappear. For the determination of the question of their occur-
rence in these situations, it is essential that such other bodies as
may be, and have been, in some instances mistaken for them, should
be well known.
The appearances in the blood which I have to record to-night
have been already described by myself or others, and I have but
little that is new on the subject now to offer. Mistakes, how-
ever, that have been made—in one case in a report published quite
recently—show that these phenomena are by no means generally
known or recognized.
1. Max Schultze’s Corpuscles.—The first instance to be here
mentioned is, that in the blood of man and many animals, besides
the red and white corpuscles there are present normally, though
in very variable numbers, small corpuscular bodies, the nature of
which has been the subject of great diversity of opinion, and is
far from being as yet determined. These are known as Max
526 Transactions of the Society.
Schultze’s corpuscles, so-called from their first observer. The
most careful investigation of these is that by a Fellow of this
Society, Dr. Osler,* who has given a full description of them,
with drawings. He observed them both within the blood-vessels
and in preparations on the slide under the Microscope, but he leaves
their nature and function quite undetermined, though his observa-
tions are valuable, inasmuch as he showed that whereas in
preparations under the Microscope they are found in masses,
within the blood-vessels they occur singly, isolated forms being
distributed throughout the blood-plasma. Though their appearance
should be familiar to every student of histology, they have un-
doubtedly often been mistaken for Bacteria, as obviously is the case
in the recent report of one of the most important investigations
of the day, to which I have just referred—a circumstance
which fully justifies their careful examination and description in
this relation. In size they are very variable, from half the diameter
of a red corpuscle to very much less. In shape many are spherical
or discoid, some pyriform, or more exactly, shaped like a comma,
or spermatozoon-like, as Osler terms them; others quite irregular.
Some appear distinctly coloured as the red corpuscles, though paler,
from their smaller size or thickness.
I have made frequent and prolonged examination of these
bodies, and can state from my own observations, that they are not
independent organisms or microphytes, as has been supposed, and
I believe that. a large portion of them at least, are mere débris,
disintegrated red corpuscles; they may be indefinitely increased in
numbers, with identically similar forms, by treating a preparation of
blood on the slide with a 10 per cent. solution of sulphuric acid ;
though somewhat strangely, this has been stated to be a good
preservative fluid for the red corpuscles.
It has been shown by Riess that they have a pathological
significance, in so far that they vary in number in different states
of health; it also seems to me that they increase and diminish at
certain periods of the day, as do the white corpuscles; both these
conditions agree with the view that they are disintegration products ;
and if this be so, their numbers would probably be enormously
increased in cholera and similar wasting diseases, in the abnormally
active metabolism of the tissues. On the other hand, however,
they appear to have been regarded by some as representing an
early stage of the development of the red corpuscles, the so-termed
hematoblasts, but the description of these is so vague that it is
difficult to arrive at any conclusion respecting them.
It. appears to me, however, that in many cases in the descrip-
tions of these corpuscles hitherto published, bodies of two different
characters have been classed together, the one of regular discoidal
* Pyoc. Roy. Soc., xxii. (1874) pp. 391-8, and Mon, Mier. Journ., 1874.
On some Appearances, &c. By G. F. Dowdeswell. 527
or spherical form, very variable in size, from the most minute up
to nearly half that of a red blood-corpuscle ; these appear to be
the blood-plates of Bizzozero, and very possibly have an evolutional
significance: those of the other class, which more particularly relate
to the present subject, are always comparatively small, and more or
less irregular in form as above described.
Though the bodies here in question—Max Schultze’s cor-
puscles—are not mentioned in many treatises on microscopic
anatomy, yet as they appear to be always present in varying
numbers in the blood, whether they are evolutional or involu-
tional forms, they must be regarded as part of its normal
constituents ; and with respect to the subject here under con-
sideration, viz. investigation of the micro-organisms which occur in
these situations, must not be overlooked. ‘The occurrence of the
mistake I have mentioned, which shows that they are not always
well known, where pre-eminently they ought to be so, has induced
me to refer to these bodies at some length.
2. Proteid or Addison’s processes of the ved corpuscles.—The
next appearances which I have to mention, resemble Bacteria
far more closely than the former, indeed morphologically they are
indistinguishable from them; they have been described by several
writers independently, in many cases apparently without knowing
what had been observed by others. In general, in a preparation of
blood under the Microscope, they appear first as small protuberances
or bud-like processes on the surface of the red corpuscles, very
similar to the first stage of gemmation in a yeast-cell; these some-
times develope—as when the preparation is treated with a 5 per cent.
solution of ammonium chromate—to broad pseudopodial processes,
in some cases of comparatively considerable dimensions; at other
times they form long fine filaments, apparently continuous, unseg-
mented, three omfour times in length the diameter of the corpuscle,
of variable thickness, but frequently so fine as to be with difficulty
recognizable with the highest powers of the Microscope; at other
times they form rosaries of minute spherules, similar to the torula
form of micrococci, or the spores of Penicillium. In general they
very shortly become detached from the parent corpuscle, and may
then be observed free in molecular movement in the field of view,
simulating exactly Micrococci, Bacteria, or Bacilli; at other times
they are retracted within the plasma of the parent corpuscle. I
have previously regarded this occurrence as due to the spontaneous
contractility of the substance of the red-corpuscles, thereby shown
to be protoplasmic ; but I must here qualify that opinion, inasmuch
as it has lately been demonstrated in a very ingenious experiment,
by Haycraft, of Edinburgh,* that egg albumen, inclosed in an
indiarubber ball perforated with minute apertures, and placed in a
* Proc. Roy. Soc, Edin., 1880-1, p. 29.
528 Transactions of the Society.
neutral solution of suitable specific gravity, upon the ball being
pressed will throw out filamentous processes, which are retracted
on the ball again expanding, showing that such processes are not
necessarily protoplasmic; they, however, demonstrate another
point in the constitution of the red corpuscles, viz. that they have
no true cell-wall or membrane, as has been sometimes supposed.
These appearances were first described and figured in the Quart.
Journ. Micr. Sci. for 1861, by the late Dr. William Addison, F.R.S.,
and after him may be appropriately termed Addison’s processes.
He induced them by treating blood on the warm stage with a
solution of sherry and salt solution or quinine; they may also be
produced by many other reagents and conditions, as I have previously
described in the same journal, 1881, where I have collated the
previous observations upon them. They are readily produced
by solutions of septic matter, and I have frequently observed
their occurrence spontaneously—that is without the addition of
reagents—in the blood of septichzemia examined under the Micro-
scope, where they have also been observed by others, but without
apparently recognizing their nature. In the report of the French
Cholera Commission in Egypt just published,* filamentous processes
from the red corpuscles of the blood kept in the incubator for
some days} are recorded, but without further observations upon
them. ‘They probably occur also in many other pathological condi-
tions. They are produced by heat, as described and figured by
Dr. Beale and by Max Schultze, through a mere disintegrating
action; also by treatment with gas, as recorded and figured by
Professor E. Ray Lankester. In the blood of the frog they occur
conspicuously, and are more readily produced there than in the
higher animals. The appearances herein have been described in
sensational terms by some German writers, but so vaguely that it
is impossible to be certain what is intended, whether these pro-
cesses of the red corpuscles or true micro-parasites, one form of
which has been fully described by Professor Lankester ; others are
said to occur frequently at certain seasons, but I have not been
able to confirm this latter observation.
These processes when detached from the parent corpuscle, are
not, as | have said, to be distinguished morphologically from Bac-
teria, and their behaviour to micro-chemical reagents is difficult
to observe, from the impossibility of keeping these minute bodies
within the field of view. Upon and during such treatment they
are not appreciably swelled or decolorized by water, as are the
red or white corpuscles; nor is the action of acids or of alkalis
much more apparent; they may, however, be distinguished from
* “Archives de Physiologie Normale et Pathologique,’ 1884, p. 411.
+ And others after a longer interval, at the temperature of the air (Lostorfer’s
corpuscles ?).
On some Appearances, de. By G. F. Dowdeswell. 529
Bacteria by their behaviour with the anilin dyes, by which, as by
methyl-anilin-violet, they are only stained faintly, like the red
corpuscles, while all forms of Bacteria, with a very few exceptions,
are readily and deeply coloured by this salt. Since the publication
of my own account of these bodies, their formation by the action of
some reagents has been observed and described by Dr. Stirling,*
and most recently in the blood in cholera as mentioned above.
Conclusion.—Thus it is seen that there are several appearances in
the blood which may readily be mistaken for micro-parasites—to
use acomprehensive term—though the occurrence of the latter is
probably more frequent in abnormal and pathological conditions
than yet recorded. The increasing importance of this subject renders
it desirable that every observer should be familiar with these
appearances. I pass over here coagula, granules, and pigment, which
frequently occur in blood, the external form of which, if carefully
observed, sufficiently distinguishes them from the cells of living
organisms.
But while, on the one hand, other bodies are mistaken for
Bacteria, in some cases veritable forms of the latter have been asserted
to be but fibrinous coagula, or in another case mere organic
crystals.
Apart from the subject of pathological appearances and the
occurrence of foreign or parasitical bodies in it, the normal
form elements of the blood, after the observations of nearly
two centuries, are far from being exhaustively known; the
varieties of the white corpuscles, of which there are several,
have been little more than suggested; some phases in the evolu-
tion of the red corpuscles, as is asserted, have been but very recently
observed; whilst the functions, origin, and destination of Max
Schultze’s corpuscles are scarcely more than conjecture: and
whilst, on the one hand, the micro-parasites of the blood, its
abnormal or pathological features, furnish a subject for examination
with, and an excellent test for, the highest powers of the Micro-
scope, its normal characters offer a field of investigation for
moderate powers, with a prospect of most valuable results, one that
is always readily available, but which has hitherto been somewhat
neglected by microscopists generally.
* Journ. Anat. and Physiol., 1883.
530 Transactions of the Society.
XIV.—On Protospongia pedicellata, a new compound
Infusorian.
By Freprerick Oxury, F.R.M.S.
(Read 11th June, 1884..)
Tuts interesting organism was first discovered by me in a pond near
Snaresbrook, Essex, in the spring of the year 1882. I was search-
ing the numerous ponds in that neighbourhood for Voluox globator,
and happened to dip a bottle amongst some rushes in a quiet
corner, which appeared to be a likely place to find what I was
looking for. On holding the bottle up to the light I observed in
it a number of minute flocculent bodies, the nature of which I could
not determine with a pocket-lens, and therefore carried them home
for further examination.
With the Microscope I found them to consist of colonies of
monads possessing collars and flagella, and connected together in
vast numbers and in rather close proximity to one another on the
periphery of some exceedingly transparent hyaline substance. _
Being out of health, and, moreover, having only a very slight
acquaintance with the group of Choano-flagellata, derived from Mr.
Saville Kent’s papers in the ‘Popular Science Review’ and
‘Monthly Microscopical Journal,’ and from some specimens shown
me by my friend Mr. Charles Thomas, of Buckhurst Hill, I did
not at that time recognize that any new discovery had been made, but
I gave some specimens to Mr. Thomas which we examined toge-
ther, and also spoke of them to another microscopical friend,
Mr. C. Livingston, who resides near the pond out of which they
had been obtained.
In the spring of the present year, 1884, I again visited the
pond in company with Mr. Livingston and Mr. Thomas, and there
found the organism again in greatabundance. Mr. Livingston took
great interest in the little creatures and examined them under very
high powers, and made measurements and computations from which
it appeared that the bodies of the individual monads are from the
1/3000 to the 1/2500 of an in. in length, the collars when ex-
tended being about twice, and the flagella five to seven times the
length of the bodies, and that the number of individuals composing
a colony amounted to from 10,000 to 20,000 or more. Mr.
Livingston was not able from Kent’s ‘ Manual of the Infusoria’ to
identify the species, the nearest approach to it appearing to be
that described by Mr. Kent under the name of Protospongia
Hicker. Ue therefore sent Mr. Kent some specimens for identi-
fication. Mr. Kent considered the specimens undoubtedly new, and
interesting to him as tending to support the conclusion he had arrived
On Protospongia pedicellata. By Frederick Oxley. 531
at as to the relationship between the Infusoria and the sponges, but
being on the eve of his departure for Tasmania he was unable to
pursue the subject. Mr. Kent also pointed out the fact, which my
friends’ and my own observations have since confirmed, that each
individual monad is furnished with a short pedicel or footstalk by
which it is held in position in the zoocytium, this footstalk, accord-
ing to Mr. Livingston’s measurement, being about the 1/10,000 of
an in. in length.
Specimens, accompanied by a short description, were sent to
Herr von Stein, who gathered from the description that the
species was new; but the specimens themselves were lost in the
post. A specimen mounted with osmic acid has, however, since
been sent, which has enabled him to confirm his opinion.
The drought we have experienced for some weeks past has so
dried up the pond from which my specimens were obtained, that no
more are to be had at present, and I have not therefore been able to
satisfy myself that Protospongia pedicellata agrees in all points
with Mr. Kent’s description of the genus; but so far as my obser-
Fic. 85. Fig. 86.
vations have extended, it differs from P. Hackeli
in the possession of a footstalk and in the num-
ber of individuals comprised in a colony, fifty or
sixty only being the number assigned by Mr.
Kent to P. Hackeli, whilst I have not met with
any colony of P. pedicellata that did not contain
a thousand or more.
I am indebted to Mr. Thomas for the
drawing accompanying this paper (fig. 85),
which is an attempt to represent the appear-
ance of a moderate sized colony as viewed by a 2/3 in. objective
with A eye-piece, but no drawing can give an adequate idea of the
beauty of the organism when illuminated by the paraboloid and
displaying its thousands of flagella in active vibration causing the
entire colony to sail slowly about the field of view. Fig. 86 repre-
sents an individual monad very highly magnified showing the
footstalk.
532 Transactions of the Society.
The collars are of course not seen in these circumstances, as
they require a high power to observe them properly, but after
haying been seen and studied under a 1/16 they are easily recog-
nized with a 1/4 in. or even a 2/3 under favourable circumstances
of illumination. ‘The mucilaginous zoocytium can only be seen
with difficulty owing to its extreme transparency and freedom
from foreign particles, and is best distinguished under black-ground
illumination with a low power.
The shape of the colonies is usually more rounded than that
of the specimen from which Mr. Thomas’s drawing was taken,
sometimes approaching a spherical form, but always presenting
indications of having been attached to some other body. They
probably grow on the stems of rushes, &c., but attached so slightly
as to be easily displaced when the water is agitated by dipping a
bottle, mouth downwards, amongst the rushes, moving it about
a little and then suddenly reversing it, taking care not to stir up
the mud from the bottom of the pond.
(5385)
XV.—On a New Form of Polarizing Prism.
By C. D. Anrens.
(Read 11th June, 1884.)
Tue prism which I desire to bring to the notice of the Society is
intended for use either as a polarizer or an analyser. It will, I
hope, be found especially useful as an analyser for the Microscope.
The employment of a Nicol prism above the eye-lens is
subject to the great inconvenience that, owing to the necessary
length of the prism, the eye of an observer is so far removed
from the lens that a portion of the field is cut off. Double-image
prisms of the usual construction are shorter, but they have another
defect, viz. that the angular separation of the rays is so slight
that the eye sees both images at once, and some confusion is thus
caused.
My object in constructing this improved prism has been to
obtain a much wider separation of the two beams of light; so
that one of them, although not actually removed entirely by total
reflection (as in the Nicol prism), is so far refracted to one side
that it may be neglected altogether. I made several attempts to
construct such a prism some years ago, but failed (as probably
others have done) owing to the difficulty or impossibility of avoid-
ing distortion and colour, and of obtaining a wide separation of the
ordinary and extraordinary rays in a prism made up of only two
pieces of Iceland spar.
I have now effected the desired object by making the prism of
three wedges of spar cemented together by Canada
balsam, as shown in the accompanying drawing (fig.87). Fa. 87.
The optic axis in the two outer wedges is parallel to
the refracting edge, while in the middle wedge it is
G
perpendicular to the refracting edge, and lies in a
plane bisecting the refracting angle. This disposition
of the optic axis is the one originally suggested by
Dr. Wollaston, and has the effect of causing a greater
angular separation of the rays than Rochon’s construc-
tion. By the employment of three prisms instead of
two I am able to give the middle prism a very large
angle, and yet to correct the deviation of the rays so far
that on emergence they make approximately equal angles with the
central line of the combination.
Nearly in contact with one of the terminal faces of the prism
I place a prism of dense glass of such an angle that it just corrects
the deviation of one of the rays and also achromatizes it, while it
increases the deviation of the other ray to such an extent that it
t
b
e
~
o4. Transactions of the Society.
may be practically disregarded altogether; an eye, even when
placed almost close to the prism, receiving only the direct beam.
This beam is, of course, perfectly polarized in one plane, and can
by a proper arrangement of the glass compensator be rendered
practically free from distortion and colour.
Other methods of effecting the compensation have suggested
themselves in the course of my work, and I have obtained the
best results by adopting the arrangement represented in fig. 88.
In this, the glass compensating prism, instead of being
Fic. 88. | mounted separately, is cemented upon one of the
terminal faces of the compound spar-prism ; the angle
G of this latter, and also of the other terminal face, being
suitably modified.
This seems distinctly preferable to the original
arrangement, for several reasons.
1, The total length of the compound prism is
rather less, being scarcely more than twice its breadth.
2. The field is rather larger, so that the prism can
be used over deeper Microscope eye-pieces (A and B)
without any of the field of view being cut off.
3. The whole arrangement is more compact, all the compo-
nents being firmly cemented together, and therefore not liable to
accidental displacement.
4, There is less loss of light by reflection, the reflecting surfaces
being reduced to two.
A ray of light entering the prism in a direction parallel to its
axis is divided into two rays; one of which, on emergence, follows
a course parallel to that of the original incident ray, and is practi-
cally free from distortion and colour: the other ray is deviated to
the extent of about 59° 30' (for yellow sodium light), being, of
course, strongly coloured and distorted. The angular separation
is so great that this latter ray does not interfere with ordinary
observations.
I hope that the prism, which has cost me much time and labour,
will meet with the approval of the Society, and take a place as a
useful accessory to the Microscope and other optical instruments.
SUMMARY
OF CURRENT RESEARCHES RELATING TO
AO b6G Y AND BOTANY
(principally Invertebrata and Cryptogamia),
MICROSCOPY, &c.,
INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.*
ZOOLOGY.
A. GENERAL, including Embryology and Histology
of the Vertebrata.
Polar Globules and other Elements eliminated from the
Ovum.}—In this important contribution to the theory of sexuality,
A. Sabatier sums up our knowledge as to the phenomena of sperma-
togenesis :—
A cellular element belonging to the so-called male gland (and not
specially an epithelial cell) grows and acquires a thicker zone of
protoplasm ; this first differentiation gives rise to the primitive re-
productive cell; this cell multiplies by division of the nucleus and
of the protoplasm ; the resulting agglomeration or group of cells is
that which forms the male tubes of Pfliiger, or the polyblasts. The
first generation of cells (protospermoblasts) becomes more or less
independent, and gives rise to one or more generations of protospermo-
blasts.
Later on, each cellular element, which is definitively male,
acquires a thicker “atmosphere of protoplasm,’ while in the zone
which is in direct contact with the nucleus there arise, by concentra-
tion and differentiation, that is to say by true genesis, homogeneous
hyaline corpuscles, which undergo a further differentiation, and
may multiply by simple division. These corpuscles, once formed,
take a centrifugal direction, pass to the periphery of the cell, and
become converted into spermatozoa. In this way is formed the
deutopolyblast, at the surface of which the deutospermoblasts are
eliminated.
* The Society are not to be considered responsible for the views of the
authors of the papers referred to, nor for the manner in which those views
may be eoapaned, the main object of this part of the Journal being to present a
summary of the papers as actually published, so as to provide the Fellows with
a guide to the additions made from time to time to the Library. Objections and
corrections should therefore, for the most part, be addressed to the authors.
(The Society are not intended to be denoted by the editorial ‘* we.”)
t Rev. Sci. Nat., iii. (1884) pp. 362-462.
5386 SUMMARY OF CURRENT RESEARCHES RELATING TO
The spermatozoa, which are derived from these last, obtain their
nutriment from the nucleus or the protoplasm of the male cell.
When completely developed they are detached, become free, and are
capable of acting as male elements. The nucleus undergoes dis-
ageregation. } ;
Between the early history of spermatogenesis and oogenesis there
is a remarkable resemblance, but there is a difference on which the
author specially insists; in the female element the multiplication of
the ovular elements is generally limited to an early period, so that
the female tubes of Pfluger contain a proportionately small number
of ovules, each of which is of a considerable size, while, on the other
hand, the male cells undergo a relatively more numerous series of
segmentations, and the resulting elements are large in number and
small in size. The view of many authors that the fundamental
process of spermatogenesis is a simple succession of cell-divisions,
ending in the formation of a cell small enough to be a spermatozoon is
erroneous. .
The essential conditions of oogenesis are the following :—
A cellular element of the tissue of the ovary (not specially an
epithelial cell) grows and acquires a more important layer of proto-
plasm; the nucleus multiplies more or less by division; each of the
nuclei acquires an atmosphere of protoplasm, and we thus have the
female tubes of Pfliiger. The fundamental distinction only becomes
apparent in the fourth stage, when the ovules, increasing in size,
become differentiated by segregation and concentration, that is, by
the formation of corpuscles, more or less hyaline, which make their
way to the surface of the ovule. Here the essential difference com-
mences, for in one case the centrifugal elements are developed and
organized at the expense of the central element or nucleus, which is
lost in the nourishment of the peripheral elements, in the other
cases it is the centrifugal or peripheral element which is broken up
or serves as food for the development of the central element, which
then forms the egg.
From these facts it is clear that the two elements of different
Sexualities are the result of the elimination of one of them from a
cellular body which at first possessed them both, and were, therefore,
capable of a parthenogenetic mode of development. :
The theory of sexuality put forward by Sabatier allows us, in his
opinion, to understand how it is that one and the same sexual gland
may, as in the ovotestis of hermaphrodite molluscs, give rise to both
male and female elements, as well as such cases as those of Bufo,
where one end of the organ is male and the other female ; the theory
applies likewise to the occasional hermaphroditism in Vertebrates,
which, most pronounced in Serranus, has been noticed by various
observers in other Vertebrates, and even in man (Heppner).
The sexual element is not always completely differentiated after a
single elimination ; two or even more may be necessary, and this is
especially the case with the female. The sexuality of the reproductive
cell is due to the appearance of the precocious globules or “globules
de début”; though a cell which has suffered such an elimination is
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 537
truly an ovum, it is in many cases not completely so ; later eliminations
are often needed to complete the work.
The different kinds of globules given off from the egg-cell
between the time when it is an asexual cell and a complete ovum are
these :—
1. Precocious globules which generally form follicular elements,
and which give, so to speak, the first impulse to the cell towards
a sexual condition.
2. Globules which are more or less tardy in putting in an appearance,
and which may be formed some time before or only just before
maturity ; like the first, they arise by a simple differentiation in the
protoplasm, and not by karyokinesis; they are the “ globules tardifs ”
properly so called.
3. There are globules which are cotemporaneous with the period
of complete maturity, or the globules of perfect maturity. Most of
these are due to phenomena of cell-division, and they are the polar
globules properly so called.
The author thinks that it is an error into which all embryologists
have fallen to regard the cellular nature of the polar globule as a
point of capital importance ; the principal, the necessary thing is the
expulsion of a mass of protoplasmic substance which represents the
male element ; it is only an accident that it is effected by a cellular
mode of segmentation. The essential fact is, in other words, the
completion of a sexual polarity.
The lesson to be learnt from all the known facts may be thus
summed up: Their common and very general character proves them to
be of the highest value; they all point to an elimination, or a ten-
dency to elimination, of a differentiated or undifferentiated portion
of the central protoplasm, and they show that the concomitant
phenomena are due to secondary circumstances which have no real
importance on the significance of the globules or of the substances
expelled by the egg.
Considerable support, even if not categorical demonstration of the
validity of Sabatier’s theory, is to be sought for in a comparative
study of the method of oogenesis in animals which are both sexually
and parthenogenetically reproductive ; if the theory is applicable to
the facts, we ought to find in parthenogenetic eggs either a complete
absence of, or a relatively small number of eliminated elements, the
number and presence of which in sexual cells ought, on the other
hand, to be distinct and pronounced.
What observations (as yet few in number) the author has made on
the history of the ova in Aphides seem to afford him the support he
needs ; still stronger support is given by Weismann’s account of what
obtains in the Daphnoidea,
In his historical survey Sabatier refers, of course, to the well-
known views of Balfour, and points out that that embryologist looked
upon the portion of the germinal vesicle which the polar globule con-
tained as being the essential point in the sexuality of the egg, and he
urges that the phenomena of karyokinesis are of no real importance ;
Ser, 2.—Vot. TV. PAY
538 SUMMARY OF CURRENT RESEARCHES RELATING TO
we must, however, note that the author speaks of “les obscurités et
les indécisions des idées de Balfour,’ and cannot refrain from sug-
gesting that it is possible that the English naturalist has suffered in
translation. In many points, Balfour’s article, published in 1878, is
in complete agreement with that now before us.
Sabatier tells us that his essay is to be looked upon as offering a
rational explanation, which may be acceptable for the present, and
promises a future essay on the relations of heredity to the sexual
polarization of the elements.
Embryonic Germinal Layers and the Tissues.*— A. Kélliker
states the conclusions of a valuable descriptive and critical essay in the
following terms :—
1. In all multicellular organisms all the elements and tissues arise
directly from the fertilized egg-cell and the first embryonic nucleus ;
and there is no such difference as is expressed by the terms archiblast
and parablast.
2. The tissues first differentiated have the characters of epithelial
tissues, and form the ectoblasts and endoblasts.
3. All the other tissues arise from these two cell-layers ; they are
either directly derived from them, or arise by the intermediation of a
median layer, which, when developed, takes an important part in
forming the tissues.
4, When the whole of the animal series is considered, each of the
germinal layers is found to be, in certain creatures, capable of giving
rise to at least three, and perhaps to all the tissues; the germinal
layers cannot, therefore, be regarded as histologically primitive
organs.
5. In birds and mammals there is no primitive organ for the
formation of connective substance, blood, or vessels.
6. The elements of tissues already formed have, as it seems, the
power of forming other tissues; those of the heterologous neoplasms
are probably due to the remains of the embryonic cells or to elements
similar in character to them.
7. There is no justification for the classification of the tissues as
archiblastic and parablastic, but, on the other hand, the old division
of the tissues under four primary types, as suggested by the author and
by Leydig, is still the most appropriate.
Origin of the Mesoblast of Cartilaginous Fishes.t—C. K.
Hoffmann commences his essay with the description of a develop-
mental stage of Pristiurus metabolicus, which is a little later than
Balfour’s stage B. In this there is as yet no trace of the notochord,
and the mesoblast is only beginning to be formed. There is still a
distinct medullary groove, and the intestine is in course of for-
mation.
The study of a number of sections, here described from before
backwards, proves that the mesoderm forms a bilateral cellular layer,
which grows forwards and backwards. Anteriorly it commences
* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 179-213 (2 pls.).
t Asch. Neerland. Sci. Exact. et Nat., xviii. (1883) pp. 241-58 (2 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 539
with the bilateral evagination of the primitive intestine, so that it
arises by delamination. This mode of development appears, however,
to obtain only during the period in which the intestine is not yet
formed. When the intestine becomes a closed tube, the mesoderm
is formed directly at the expense of a mass of indifferent cells; in
other words, the endoderm and the mesoderm are intimately united
at the point where the embryo is growing forwards. The part of the
mesoderm formed by a process of delamination is, comparatively, very
small. At the edgesof the blastoderm and of the blastopore—the
point where the embryo grows backwards—the three germinal layers
are closely united.
The notochord is formed by the endoderm, and, like the mesoderm,
it grows forwards and backwards. Anteriorly the layers are so
closely united that the cord there appears to be solid, and the anterior
portion of the notochordal groove is, therefore, only feebly developed.
Posteriorly the delamination is very pronounced, and the groove is
wide and deep. The animal portion of the endoderm, or that which
gives rise to the notochord, is separated, on either side, by a narrow
but distinct cleft from the intestinal endoderm. Anteriorly the
notochordal and intestinal endoderm are completely fused, and directly
continuous with one another; posteriorly they are for a long time
independent. This would seem to show that the mesoderm originally
arose, at the hinder extremity, by a bilateral delamination of the
primitive intestine, and this has, in the course of phylogenetic deve-
lopment, been replaced by a process of folding.
The author applies his knowledge of the development of the
cartilaginous fishes to an explanation of the phenomena of the de-
velopment of the notochord and mesoderm in birds; and comes, in
conclusion, to the result that the phenomena observed in the mero-
blastic ova of cartilaginous fishes amply demonstrate the truth that
there is no well-marked division between mesoblast and mesenchyme,
as has been insisted on by the brothers Hertwig. In these fishes
only a small part of the median germinal layer is formed by the
bilateral evagination of the primitive intestine—the mesoblast of
the Hertwigs. The greater part of the layer would be, for the
Hertwigs, mesenchyme. As a matter of fact, the two unite so early
that it is impossible to say which had the earlier origin. The cells
of the part which arise as mesenchyme have the same epithelial
appearance as those which are formed by the evagination of the
primitive intestine. The body-cavity—enterocele—which was at
first found only in the part of the median layer which arose by
delamination, soon extends into the region which, from its mode of
origin, should be called mesenchymal.
Intra-cellular Digestion in the Germinal Membrane of Verte-
brates.*—J. Kollmann commences with an account of his observations
on the cells of the endoblast in the lizard ; these cells vary consider-
ably in size, and in their protoplasmic contents one finds spheres
which are to all appearance of a fatty nature, and which are also
* Recueil Zool. Suisse, i. (1884) pp. 259-90 (1 pl.).
202
540 SUMMARY OF CURRENT RESEARCHES RELATING TO
present in large numbers in the fluid yolk; the nucleus of the endo-
blast-cells is most remarkable for the changes which it undergoes in
position. The author was most struck by the cells which appeared
to open superiorly, and took them at first for artificial products;
observation, however, led him to conclude that this was a definite
physiological stage, and that being so he is compelled to suppose that
the endoblast-cells do not merely maintain existence by diffusion, but
also by direct massive wandering; there would appear to be not only
a completely mechanical intaking, but as complete an outgiving of
yolk-spheres.
The author has also made some observations on the chick, and
the result of his studies is his conviction that the cells of the
endoblast take up food in an amceboid manner. He finds that ecto-
blastic cells have a similar power of incorporating yolk-material,
which they do by means of amceboid movement. In Lacerta agilis
he has observed protoplasmic processes directed towards the vitel-
line membrane, and has found in the interior of the cells small
yolk-granules, and others which seemed to have been just incor-
porated.
In the acroblasts—as Kollmann terms the cells in the layer which
lies between the ectoblast and endoblast—each of which is quite
independent of the mesoblast, and in the cells derived therefrom
which he calls “ poreuten,” a similar phenomenon has been observed.
The latter are quite easy to find in the lizard, but are more difficult
of detection in the chick, where they can only be seen after staining.
In the lizard the author has been able to observe a direct movement
of masses from the endoblast to the poreutes, a poreute sending out
processes towards an endoblast-cell.
The author concludes with referring the reader especially to the
work of Metschnikoff, in connection with which he would wish his own
fragmentary contribution to be studied.
Larval Theory of the Origin of Cellular Tissue.*—A. Hyatt
reviews the history of investigation among sponges ; concluding that,
though true Metazoa, they possess characteristics which show them
to be derived from Protozoa. The parallel between the development
of the cell and egg in the tissue is strictly parallel with the evolution
of nucleated from unnucleated forms in Protozoa. Recent investiga-
tions have removed all objections to the homology of the egg or any
cell with the adult of the nucleated protozoon; and the principal
mode of reproduction by division is the same in all these forms. The
egg builds up tissue by division after being fertilized by the male or
spermatozoon, just as the spermatozoon builds up colonies after ferti-
lization.
Spontaneous division of a cell which undergoes encystment takes
place and the spermatozoa which result from this are true larval
monads. These resemble the monads derived from division of the
encysted bodies of Protozoa in their forms and in their activity.
They differ in being able to fertilize the female or ovum at once,
* Science, iii. (1884) p. 337.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 541
instead of being obliged to grow up to maturity before arriving at this
stage.
Thus all cells may be regarded as larval Protozoa, and eggs and
spermatocysts as encysted larval forms, the spermatozoa being equi-
valent also to larval forms which have inherited the tendencies of the
mature forms in the Protozoa at the earliest stages. Thus the origin
of the tissues in the Metazoa is in exact accord with the law of con-
centration and acceleration in heredity. The cells are larval, which,
in accordance with this law, have inherited the characteristics and
tendencies of their adult ancestors in their earliest stages. The three
layers can be accounted for as larval characteristics inherited from
colonies of Infusoria flagellata, which had two forms (protective and
feeding zoons), and then three (protective, feeding, and supporting),
these corresponding to ectoderm, endoderm, and mesoderm.
Development of Protovertebre.*—H. Fol, from a number of
experiments on the order ef appearance of the protovertebre of the
common fowl, comes to the conclusion that “ the first-formed somites
of the body appear to be the most anterior of the whole series, and
that they correspond, perhaps, to the cephalic region ; the long series
of protovertebre are formed successively from before backwards.”
Thus the vertebrate embryo commences, so to speak, as a head only, the
rest of the body appearing by degrees.
Experiments in Arrested Development.{—Another communication
by M. Fol deals with some observations made by himself and §.
Warynski which tend to confirm a previous discovery, that by
momentarily heating the left side of an embryo chicken, a complete
visceral inversion is obtained. The experiments consisted in pressing
with the blade of a scalpel a portion of the embryo without injuring
the vitelline membrane ; by so doing, the development of that portion
lying outside the line of pressure was completely stopped. The de-
velopment of the left side of the embryo was hindered by separating
it from the afferent portion of the vascular area, and it appears to be
by an arrest of development of the left side that a visceral inversion
is produced, “ from which it may be concluded that this side ought to
predominate to bring about the normal torsion.”
Morphology of the Directive Corpuscles.t—O. Biitschli points
out that, for a satisfactory comprehension of the morphological
significance of the directive corpuscle, it is necessary to bear in mind
the mode of sexual reproduction in the colonial Volvocinesr, a group
of the Flagellata, which not only by their structure, but also by the
characters of their method of reproduction, approach most closely to
the Metazoa, even though their mode of nutrition is vegetable in
character. The simplest case of sexual reproduction has been made
known to us by the researches of Pringsheim on Pandorina.
In it, at certain times, the cells of a colony give rise by successive
* Arch, Sci. Phys. et Nat., xi: (1884) p. 104.
+ Ibid., p. 105.
~ Biol. Centralbl., iv. (1884) pp. 5-12.
542 SUMMARY OF CURRENT RESEARCHES RELATING TO
division to small sexual colonies, which arise in exactly the same way
as the ordinary colonies which are merely formed by parthenogenetic
reproduction. These small sexual colonies finally break up into the
separate cell-individuals, which then copulate by pairs and form a
resting zygote; a difference between the sexes of the separate
individuals is not, or is only slightly, demonstrable. In the closely
allied genera Hudorina and Volvox the facts are very different; in
the former there appear at certain times colonies, which can be dis-
tinguished as male and female, some produce nothing but ova, others
as distinctly give rise, after repeated division, to spermatozoa, which
copulate with and fertilize the female colonies. In Volvox it seems
possible to homologize the male and female colonies, and indeed we
cannot here correctly speak of colonies, but ought rather to regard
what are so called as multicellular individuals of the simplest kind,
and we have in it the best marked intermediate stage towards the
sexual reproduction of the Metazoa.
If we bear these facts in mind it is not difficult to suppose that
the separation of a few small cells indicates the formation of a
multicellular colony of “gametes” corresponding to the bundle of
spermatozoa.
As to the physiological significance of the directive corpuscle we
have to decide between the views of the author that we have here to
do with an elimination of certain nuclear constituents of the egg-cell,
and that of Minot, that it is an elimination of the male element.
Against the latter we have the fact that in the simpler cases of
sexual reproduction in plants, as the alge, there is no process of
elimination, such as is required by the hypothesis, and also the fact
that it cannot be brought into accord with the known phenomena of
parthenogenesis.
In a note the author states that the recent observations of Fol,
Sabatier and others, only came to his knowledge after his essay was
completed, and he has not yet had the opportunity to bring them into
accord with his own views. He takes occasion, however, to refer to
some observations lately made by his assistant, Dr. Blochmann, who
has discovered a very remarkable mode of cell-multiplication in the
ovarian ova of ants; these have certainly nothing to do with the
formation of the cells of the follicle, for the ovum was already
surrounded by a chorion, before the numerous small nuclei, which
appear in an altogether unexplained way, had become developed. The
observations of Blochmann on ants are possibly to be brought into
association with phenomena observed in the ova of Myriopods and
Tunicates.
Morphology of the Pineal Gland.*—F. Ahlborn has a short
essay on the significance of the pineal gland, a subject which is of
especial interest to English students on account of the recent hypo-
thesis of Sir Richard Owen. The author comes to the conclusion that
the pineal gland of vertebrates is to be regarded as the rudiment of
an unpaired optic rudiment, and he bases this conclusion on the
* Zeitechr. f. Wiss. Zool., xl. (1884) pp. 331-7 (1 fig.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 513
similarity in the mode of its development and of the optic vesicle,
that is, by a hollow outpushing of the central wall; on the origin and
connection of the epiphysis with the optic region of the brain, and
especially with the thalamus opticus; on the morphological resem-
blance between the organ and the primitive optic vesicle; on its
almost peripheral position in Petromyzontes, Selachii, and Ganoids, as
well as its completely peripheral position (outside the skull and at
the same level with the eyes) in the Amphibia; and, finally, on the
primitive connection, detected by Van Wijhe, between the epiphysis
and the neural ridge.
The author, regarding the pineal gland as a frontal eye, thinks it
justifiable to compare it with the unpaired eye of the Tunicata, and
possibly also, of Amphiowus.
Segmentation of the Vertebrate Body.*—F. Ahlborn, after a
résumé of the theory of Gegenbaur as to the composition of the verte-
brate skull, points out that an advance was made when later investi-
gators discovered evidence in favour of the mesomeres of the head ;
Gotte, who was the first in this line of inquiry, recognized four
segments in the cephalic region. The author’s own observations on
Petromyzon led him to the conclusion that the first two spinal
nerves correspond to three mesomeres, and that the first neuromere
nearly corresponds to the fourth and fifth mesomeres. From this it
seems to follow that the first three myocommata were innervated not
by a spinal but by a cerebral nerve; and that in the hinder part of the
head of Petromyzon the parts of three true mesodermal segments are
still retained. A further inquiry shows that the three first spinal
nerves of Petromyzontes and of anurous Amphibia are completely
homologous, and that the first cervical vertebra of the Amphibia
corresponds to the fourth myocomma of the lampreys; if this
result be correct it follows that the three first myomeres of the
lampreys—which we have already recognized as typical cephalic
ents—are homologous with the three hinder segments of the skull
of the Anura. This remarkable agreement is further supported by
the close systematic relation between these two groups which is
spoken to by the large number of characteristics that they have in
common.
Gitte was followed by Balfour who attacked the problem by the
road of the developmental history of the Elasmobranchii, and demon-
strated the presence of a somatopleure and a splanchnopleure in the
mesodermal elements of the head, as of the trunk; this considerable
support to the doctrine of the metamerism of the head by the dis-
covery of the head-cavities was succeeded by Marshall’s investiga-
tions, which resulted in showing that metamerism first appeared in
the ventral (or branchial) portion only, and by Van Wijhe’s work
along the lines of the same theories. The studies of the last-
mentioned anatomist lead to the conviction that the mesomerism,
which is independent of the branchiomerism, as Marshall proved for
the anterior, is true for the whole of the cephalic tract; it is a
* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 309-80.
544 SUMMARY OF CURRENT RESEARCHES RELATING TO
typical segmentation which, primitively, completely agrees with the
primary metamerism of the mesoblastic somites of the trunk. Of
these cephalic somites there are nine. We may, in fine, conclude that
the head of the Vertebrata ordinarily contains nine mesodermal
segments, which, like the segmental musculature, might become of
use to the specific cephalic organs ; but the earlier stages generally
disappear and the metameres are no longer clearly seen to be separate
segments.
Ahlborn next addresses himself to the question of whether the
gill-arches are homodynamous with the ribs, and comes to the con-
clusion that the history of development clearly shows that the
metamerism of the gill-arches, which according to Gegenbaur’s hypo-
thesis is an expression of the primary mesomerism of the skull, is
really nothing of the kind, but a segmentation which is caused by
the primary branchiomerism of the enteron, and completely inde-
pendent of the segmentation of the mesoderm. This conclusion is
found to be confirmed by what obtains in Petromyzon and the Anura;
the whole answer may be summed up in saying that the ribs are, but
the gill-arches are not, segmental.
The other problem proposed is: How far have the cerebral and
spinal nerves a segmental nature, of the kind supposed by Gegen-
baur? No primary segmentation affects the nervous system. Neuro-
merism, therefore, is in the peripheral nervous system nothing
more than a secondary repetition of all the pre-existing metameric
phenomena in the body; it is segmental, when the nerves are dis-
tributed to the segments of the body, but not in the branchiomerous
organs.
If the view be just that the nine rudimentary cephalic segments
of the ancestor of the craniote Vertebrata were developed in just the
same way as the trunk-segments, and if, at the same time, the medulla
oblongata is a similar continuation of the spinal cord, we may con-
clude that there were primitively nine pairs of spinal nerves in the
hind-brain, of which the third, fourth, and sixth had only motor
roots. But at the same time the so-called spinal-like cerebral nerves
of the Craniota cannot, when we consider their morphological and
physiological significance and the secondary character of neuro-
merism, be any longer compared with the segmental pairs of spinal
nerves.
Embryology of Alytes obstetricans.*—M. Heron-Royer, gives a
detailed account of the external modifications observed during the
embryonic development of Alytes obstetricans. For the purposes of
observation the eggs were placed on moist muslin between watch-
glasses, and kept exposed to light and to a warm temperature. The
egg has a large vitellus and a small cicatrix. Segmentation, which is
limited in extent, commences after 12 or 13 hours with a dorsal
streak with a broad, shallow blastopore. The vitellus is now spheri-
cal, but soon becomes oblong with the formation of the elongated
embryo. The embryo has paired ocular lobes anteriorly, and cor-
* Bull. Soc. Zool. France, 1883, pp. 417-436 (1 pl.).
~-
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 045
responding branchial lobes posteriorly. In front of, and between,
the anterior lobes is an air-bubble supposed to be respiratory in func-
tion. By the 3rd day the four lobes have increased and coalesced to
form a “racket-shaped figure.’ During the 4th and 5th days the
cranium and sense organs (excepting the eye) are developed, the
olfactory organs appearing much later than in other Anura. The
branchie appear as digitiform processes of the lateral masses. By
the 6th day they are six in number on the right side and seven on the
left. By the 7th day there are ten for each side. In addition there
are tentacular ramifications which coil about beneath the walls of the
ovum. M. Heron-Royer compares these (provisional) organs with
the arborescent vascular processes described by M. Bavay in the
developing ovum of Hylodes Martinicencis, and justly explains
their origin by reference to the terrestrial conditions of the deve-
lopment of the young Alytes.
The heart, first observed on the 6th day, is covered merely by a
pericardium, and not by the vitelline sac, as in other Anura. On
the 8th day appears the abdominal investment, inclosing a portion
of the disappearing vitellus, and distinguished therefrom by pigmenta-
tion. By the 9th day the yellow-coloured intestine is completely
formed, and the vitellus absorbed. The eye is completed on the
13th day, when the choroidal fissure disappears, and the iris,
hitherto white, finally assumes its metallic yellow colour.
On the 14th day the external branchie disappear, the right oper-
culum being the last structure to be formed. The natatory mem-
branes now develope, the caudal appendage elongates, and the embryo
is ready to escape from the egg.
There are three investments to the egg: (1) an “external en-
velope,” inclosing an albuminous layer ; (2) an “inner capsule,” oval
in shape; and (3) the “chorion,” directly investing the ovum proper,
which is spherical.
M. Heron-Royer disagrees entirely with the previous observations
on the mode of the escape of the embryo from the egg. He finds
that the young Alytes does not (as de L’Isle and others had asserted)
simply split the envelopes of the ovum, like a bean-pod ; but rather
that the exit of the embryo is at first conditioned by moisture.
Exposed to moist conditions, the albuminous layer beneath the “ ex-
ternal envelope” absorbs moisture and expands its investment. The
“inner capsule” in the presence of the moisture becomes more supple
and allows greater freedom of movement to the embryo, which now
employs the external comb-like lamelle on its jaws to effect an open-
ing, first in the chorion, then in the ‘inner capsule,’ and finally in
the “ external envelope.” Finally, bending its body into a bow, and
fixing its tail against the capsule, the embryo, by a final effort, forces
its way from the egg “ comme un projectile.” Sometimes the young
Alytes sticks half-way or endeavours to emerge tail first, usually with
fatal consequences.
M. Heron-Royer, by applying abnormal warmth and moisture,
brought about the development of Alytes within 15 days. In normal
circumstances, however, 24 days intervene between fecundation of
546 SUMMARY OF CURRENT RESEARCHES RELATING TO
the ovum and the escape of the embryo, the male Alytes retiring
with the eggs wound round its legs to holes in the ground away
from light and warmth. On warm nights in July (with the thermo-
meter at 20°C.) the male Alytes carries his charges down to the
water, and they then effect their escape, as above described. If the
atmospheric conditions are unfavourable the Alytes, guided by “son
instinct barométrique,” defers its passage from the land to the water.
Development of the Nervous System of Forella,*—An account
is given by V. Rohon of his observations on the development of
the cerebro-spinal system in the trout. Briefly summed up, his
results are that the first nerve-cells, distinctly recognizable as such,
occur in this fish in the dorsal (sensory) tracts of the cerebro-spinal
system. These “cells of Reissner” are multipolar, lie on either side
in a longitudinal series (6 to 8 pairs in a myomere at the time of
escape of the embryo from the ovum), and occur in the spinal cord
earlier than in the brain. In the spinal cord they have relations to
the dorsal roots of the nerves of the same, and of the opposite side.
These cells occur in much the same fashion in the adult trout.
Incubation of Eggs in Confined Air—Influence of Ventilation
on Embryonic Development.;—C. Dareste describes the results of
his experiments on the development of the embryos of fowls in a con-
fined atmosphere.
The eggs were placed in a 12-litre incubator, all the apertures of
which were kept closed for 21 days. When opened several eggs
were found hatched, but the greater number had perished, owing to
the development in the albumen of microscopic organisms. The
organism most often met with was a plant similar to yeast.
In a second series of experiments the air was saturated with
moisture, and in this case the albumen liquefied and leaked through
the shell where it solidified in layers. This liquefaction appeared to
be an obstacle to hatching ; nevertheless, the embryos from the sound
eggs had here also reached their full period, whilst those from the
infected eggs had perished, stifled by a species of Aspergillus that
developed a mycelium in the interior of the albumen, then formed
green fructifications in the air-chamber, and finally on the walls of
the shell.
The author concludes that air, modified by embryonic respira-
tion, exercises no direct influence on the development and life of the
embryo; but only an indirect one by facilitating the excessive deve-
lopment of the parasitic organisms. Hence the necessity of renewing
the air of incubators. In the struggle for life between the embryo
and the parasites the advantage is in favour of the former, if the air
be renewed and is sufficiently dry; whilst in air that is stale or
saturated with moisture the advantage is in favour of the parasitic
organisms.
* SB. K. Akad. Wiss. Wien, 1884, pp. 39-56 (2 pls.).
+ Comptes Rendus, xcvili. (1884) pp. 924-6.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 547
B. INVERTEBRATA.
Effect of High Pressure on the Vitality of Micro-organisms.*
—A. Certes describes some experiments which he has made*on fresh-
water and marine micro-organisms.
At a pressure of 100 to 800 atmospheres, maintained for 7, 24,
48, and 72 hours, some were killed; Chlamydococcus pluvialis were
as lively as when they were put in the apparatus 7 hours previously ;
Paramecium colpoda and Vorticelle (800 atmospheres for 48 hours)
showed the “latent life” of Dr. Regnard.t The marine infusoria
Euplotes charon, E. patella, and Pleuwronema marina retained the
power of motion, while Holosticha flava and Actinophrys were
dead.
After 86 hours at a pressure of 520 atmospheres, the Chlamydo-
cocci were mostly in the latent state, the completely green individuals
having resisted the pressure better than those which were turning
red. MRotifers were taken out in full activity, while Tardigrades
revived after a time.
In a case of bacteridian anthrax, blood submitted to a pressure
of 600 for 24 hours maintained its full virulence.
Micro-organisms of the Deep Sea.t—The researches of A.
Certes on water and ooze from great depths tend to show that microbes
that can live without air are absent from the bottom, while air-
breathing forms are there present. The series of cultivation experi-
ments which he carried on showed that the micro-organisms of deep-
sea water were always much smaller and more active than those of
the ooze. Ciliated or flagellate infusoria were absent. Successive
cultivations resulted in the appearance of a number of large bacilli
in active spore-formation. It has not yet been possible to decide
whether the organisms found at great depths are identical with those
already known.
The researches of Regnard have shown that soluble ferments are
not affected by pressure; under the influence of 1000 atmospheres
starch was converted into sugar under the action of saliva. The
other results obtained have been already noted.§
Origin and Formation of Glairine or Barégine.||—Supplement-
ing a former paper on this subject, N. Joly describes the result of his
observations on the origin and mode of formation of glairine or
barégine in the sulphurous thermal waters of the Pyrenees. Micro-
scopical examination, with a low power, of glairine and “ sulfuraire ”
in the course of formation revealed the presence of a very consider-
able number of animalcules, Nais, Cyclops, &c., in the full vigour of
* Journ. de Microgr., viii. (1884) pp. 291-3.
+ See this Journal, ante, p. 362.
1 Naturforscher, xvii. (1884) pp. 193-4.
§ See this Journal, ante, p. 362.
|) Mem. Acad. Sci. Toulouse, y. (1883) pp. 118-25 (1 pl.).
548 SUMMARY OF CURRENT RESEARCHES RELATING TO
life, and this though the temperature of the water reaches 40° C. to
49° ©. By their death and decomposition they furnish to the water
the nitrogenous organic material which it holds in solution, and the
gradual transformation of their remains into glairine precisely similar
to that formerly observed is described by the author, who concludes
that the concrete glairine of chemists is a complex substance, into the
composition of which enters as a primordial element, a vast amount
of animal and vegetable detritus. The “ sulfuraire ” is a very different
production, but its fragments and those of various inorganic sub-
stances go to swell the mass of the glairine.
In a note to the paper is given a list of the organized bodies, to
the number of 39, that have been recorded as occurring in sulphurous
waters; whilst figures of Nais sulfurea and Cyclops Dumasti are
given in the plate.
Organisms in Hail-stones.*—Boyd Moss has, on two or three
occasions during the last twelvemonth, collected a few hailstones in
a conical glass, so that anything contained in them subsided to the
bottom as they melted, and has always found organized remains, but
he never had any idea of the quantity of these till a recent hail-
storm. He figures the contents of a single hailstone (about 1/4 in. in
diameter), which he placed, with every precaution as to cleanliness,
between the glasses of a live-box. These consisted of diatoms, a
living Ameba, a spore, probably of fungus, pale yellowish bodies like
ova about 3 to 4 times the diameter of a human red blood-corpuscle
(at least 40 of these), and a dark brown mass with small bright
spherules. The Amceba and one diatom were in active movement.
The spore (?) he calls the attention of microscopists to, and would be
glad to hear if they are acquainted with it, “as it is one of several of
the same kind which he discovered among the fibres of the heart of
animals dead from cattle disease in India in 1870, and described in
the ‘Monthly Microscopical Journal’ for December of that year,
p. 312.”
Mollusca.
Suckers of Sepiola.;—M. Niemiec describes the structure of the
suckers of Sepiola rondeletii. The general features appear to agree
pretty closely with the account given by P. Girod of the suckers of
other Cephalopods,{ but present some special peculiarities.
The sucker consists of three parts: (1) the basal portion imbedded
in the subepithelial tissues of the arm; (2) the peduncle; (8) the
sucker proper. The basal portion is surrounded by a layer of annular
muscles; within this is a longitudinal layer, while the centre is
occupied by a series of radiately arranged fibres. These three layers
are continued into the peduncle, and in the short arms terminate in
the piston of the sucker, while in the two long arms they are inserted
into a rounded cartilage. In other respects the suckers upon the
* Knowledge, v. (1884) p. £23 (1 fig.).
+ Arch. Sci. Phys. et Nat., xi. (1884) pp. 100-2.
{ See this Journal, iii. (1883) p. 636.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 549
short arms differ from those upon the long arms, the main difference
being that, while the former are furnished with muscles directly
continuous with those of the peduncle, the latter contain no muscles
at all, but only a mass of parenchymatous tissue between the two
epithelial layers.
Histology of the Digestive System of Helix.*—From a study of
H. pomatia var. grandis, Dr. F. Bonardi, who has made frequent use
of double-staining methods, finds five distinct layers in the wall of
the buccal mass, viz. (1) The outermost, of connective tissue,
consisting of a fibrillated basis and of nuclei, and of a few distinct
cells, which often contain calcareous concretions and refractive fatty
globules ; and next to it (2) muscular, in two layers,-the outer longi-
tudinal, the inner circular. They form an exception to the characters
of the muscles in this animal, in often being in appearance trans-
versely striated; this is, however, probably only owing to a pecu-
liarity in the arrangement of the fibres within the sarcolemma.
(3) Connective tissue, a continuation of the tunica connectiva of the
other parts of the digestive system, containing granular cells.
(4) Cylindrical epithelium, the cells very long; over the prominence
described by Semper in the upper and lower parts of the buccal
cavity it is ciliated. (5) Cuticula, of considerable thickness ; it is
stratified in a longitudinal direction, and some large strie placed
perpendicularly to the surface of the epithelium perhaps represent
fine canals. The tongue consists chiefly of a muscular mass; this
includes three distinct muscles, two of which are symmetrical and
posteriorly separate, so as to embrace the lingual papilla; the third
lies transversely below and unites them in the median and hinder
parts of the tongue. All are isolated by connective tissue. The
surface of the tongue is divided up by two sets of grooves into quad-
rangular spaces, on which are placed a large number of whitish
pyriform papille. The lingual papilla (at the base of the tongue) is
covered by connective tissue, beneath which lies a layer of circular
muscular fibres, covering a very distinct tunica connectiva, apparently
not hitherto observed, containing oval cells with distinct outlines,
imbedded in granular matter. It lies next to the cylindrical epithe-
lium of the radula.
The centre of the papilla consists of a transparent colourless
substance, the external parts of which, near the radula, have the
structure of connective tissue. The other parts contain fibrils going
in various directions. At certain points they are inflated and have
nuclei. They make up the “legs of the papilla,” and become mingled
with the lateral muscles of the tongue. ‘The alimentary canal (viz.
the cesophagus to the end of the duodenum) has (1) an external
connective coat corresponding to the peritoneum of the higher ani-
mals, underlaid by (2) double muscular, and (3) a connective layer
corresponding to the vertebrate mucosa, and (4) an epithelial layer
covered by a cuticula. The muscular fibres are not striated; those
of the one layer are longitudinal, of the other transverse, some
* Atti Accad. Sci. Torino, xix. (1883) pp. 33-46 (1 pl.).
550 SUMMARY OF CURRENT RESEARCHES RELATING TO
being oblique. The connective layer (3) has a lacunar structure.
The lacune are lined by a cylindrical endothelium. The epithelium
lining the depressions of the stomach, &c., may be said to be glandu-
lar ; that occurring over certain conical processes of the connective
layer is absorptive. From the distribution of the glandular and
absorptive organs, Dr. Bonardi is led to abandon the terms cesophagus,
stomach, and duodenum as expressing physiological facts. With
the exception of the buccal portion, which is used for prehension,
and the extreme posterior section, acting as an expelling organ, no
separate functions are assignable to any part of the canal. The
wall of the duct of the salivary glands consists of an outer cellular
connective layer continued from the different glandules, of a median
muscular coat comprising circular and oblique fibres, and of an
epithelium made up of small cylindrical cells, on which no cilia were
found. The refractive granules in the cells of the inner surface of
the hepatic lobules are considered, with Barfurth, to be calcareous,
but the ‘“ferment-cells” described by that author were not made
out. Numerous muscular fibres were found in the peritoneum of
the liver.
Aplysie of the Gulf of Naples.*—F. Blochmann distinguishes
three species of Aplysia in the Gulf of Naples by the following
characters :—
I. Lateral lobes free as far as the foot. A fine canal leads into
the cavity which contains the shell. Behind the genital
opening is a racemose gland.
Animal 20-80 cm. long ; black, with white and grey spots.
Aplysia limacina L.
II. Lateral lobes fused together as far as the siphon. A wide hole
without folded margins leads into the cavity which contains
the shell. Behind the genital opening a group of unicellular
glands, each of which has a separate external pore.
a, Animal 10-20 em. long; clear reddish to blackish
brown, white spots, the margins of which coalesce.
The upper side of mantle has no cilia. Aplysia
depilans L.
b. Animal 7-15 cm. long; same colour as the last, the
spots, however, smaller, and distinct, with usually a
black border. Upper side of the mantle ciliated.
Aplysia punctata Cuv.
The paper contains further details of the anatomy of these three
species, a complete list of synonyms, and a bibliography of the subject.
Morphology of the Acephalous Mollusca.j—H. de Lacaze- |
Duthiers devotes his first memoir on the ‘ Morphologie des Acéphales,’
to the remarkable Aspergillum (A. dichotomum) or Watering-pot Mol-
luse, the animal of which is so rare, though the well-known shell is
* MT. Zool. Stat. Neapel, v. (1884) pp. 28-49 (1 pl.).
t Arch. Zool. Expér. et Gén., i. (1883) pp. 665-732 (5 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. |
common enough. After an account of the difficulties which he per-
sonally suffered in trying to get these molluscs for dissection, and a
discussion of its general characters, the author describes the structure
of the shell, in which he distinguishes the true from the false shell.
The former, as is well known, consists of two small valves, and
possibly also of zones which extend beyond their limits; the latter is
tubular in form, and presents differences in sections taken at different
points. In the terminal or lower part the calcareous tissue is pretty
compact, and is formed of a number of layers which can be easily
separated from one another, and do, as a fact, so easily part that it is
impossible to make a satisfactory circular section of the tube. The
facts of structure seem to show that the secretion of the false shell and
its mode of growth depend on a deposit of crystalline particles, which,
when effected slowly, gives rise to spheres, and when rapidly, to
needle-shaped bodies. With regard to the marks or lines of attach-
ment of the muscles, which are so prominent a feature in the shells of
ordinary Lamellibranchs, it is here difficult to speak with certainty,
and such lines of insertion as can be made out are hard to describe,
inasmuch as they vary in depth in different individuals, and have not
always exactly the same contour.
To examine the animal that forms the shell it is necessary to break
the latter, for it is impossible to extract by the lower orifice a conical
body, in which the base has, of course, a longer diameter than its
truncated apex. The body hasa chitinous envelope which is probably,
though not quite certainly, secreted by the mantle; this last has no
remarkable characteristics. The description of the mantle is followed
by a general account of the structure of the animal, and the author
then passes to the digestive tube.
The dissection of the digestive tube was long and laborious on
account of the intimate relations of the genital and hepatic glands ;
as in other Lamellibranchs it describes a convoluted or appa-
rently capricious course. The form of the anus is remarkable in
consequence of its being affected by a constriction quite close to the
end of the rectum; the extremity has the form of a small spherule,
and the orifice is bilabiate. Within the interior of the intestine there
is a projection comparable to the typhlosole of the earthworm ; in the
stomach the same ingrowth has a number of folds. No cecum or
hyaline style was to be observed. The cesophagus is certainly much
longer in Aspergillum than in any other Lamellibranch; the mouth is
very easy to find, and appears to have a definite relation to the superior
orifice of the disk of the mantle. The liver, as in all its allies, is well
developed ; though the condition of his specimens did not enable the
author to make altogether satisfactory preparations, he thinks that it
agrees in essential characters with that of other Lamellibranchs.
The organ of Bojanus is heart-shaped in form and brownish in
colour ; the pericardiac orifices are relatively easy to find, and, as in
Anodon, the external orifices are situated at a high level. It is,
without doubt, the organ that was described by Riippell as the
liver.
The central organs of circulation closely resemble those of other
552 SUMMARY OF CURRENT RESEARCHES RELATING TO
Lamellibranchs, and the general plan of the vessels would seem to be
on the same type.
The gills are simple in structure and conform to the Lamellibranch
type. The generative glands are united in the same individual ; the
acini of the testis are large, smooth, or polyhedral, the ovary is also
racemose in form, and is placed behind the male organ. After a de-
scription of the nervous system and of the muscles, M. de Lacaze-
Duthiers sums up the substance of his observations by pointing out
that the animal of the watering pot shell is morphologically altogether
like that of any other Lamellibranch. After an early period in
which development goes on quite regularly, the body, owing to the
excessive growth of its lower portion and the stationary condition
of the upper, can no longer be withdrawn into its shell; then there
commences a period of abnormal calcareous secretion, which gives rise
to the peculiar form of the “shell.” But this remarkable phenomenon
does not affect the essential characters of the animal, which is much
more truly lamellibranch than Tridacna, Anomia, or the oyster.
In conclusion, the author insists on the value of commencing the
study of any given group by the consideration of the anatomy of a
normal form.
Molluscoida.
Anatomy of Rhopalea.*—L. Roule describes the structure of this
simple Ascidian, which is very abundant in the neighbourhood of Mar-
seilles. The body is divided into two halves, of which the anterior is
triangular and free, while the posterior is irregular in form and fixed ;
the two halves are united by a delicate region of some length. The
tunic, in its hinder portion, contains a number of vacuolated cells,
which are absent from the anterior. By its general facies Rhopalea
resembles the Clavelinide, but its structure and mode of development
associates it with the Phalusiide ; and it may be considered as forming
a link between the simple and compound Ascidians. In some points,
such as the postbranchial position of the viscera, it approaches Ciona
more than the true Phallusie, with which, on the other hand, it agrees
by the possession of longitudinal folds in the wall of the branchia.
Its affinities may be said to be numerous, and to form a bond of union
between several diverse groups.
Arthropoda.
a. Insecta.
Luciola italica.;— C. Emery, after some observations on the
external characters of these insects, and the differences between the
males and the females, in which he points out that in the male the
whole of the lower of the penultimate (fifth) and last abdominal
segments is phosphorescent, while in the female, which has seven
abdominal segments, only two spots at the sides of the lower surface
are luminous, passes to the structure of the luminous organs, in which
there are the following, among other, interesting points. Prepara-
* Comptes Rendus, xcviii. (1884) pp. 1294-6.
+ Zeitschr. f. Wiss, Zool., xl. (1884) pp. 338-55 (1 pl.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. jae
tions made with osmic acid showed that the smooth terminal branches
of the trachex always end freely, and that they are never connected
with other capillaries, either of their own or of other trunks; the
author is so certain of this that he thinks that the anastomoses
observed by Kélliker and others in the Lampyride can have no real
existence. The structure of the dorsal layer of the luminous plates
is very simple, no distinct cellular elements could be isolated, and
the organs whether fresh, or after treatment with various reagents,
showed nothing but opaque uric concretions floating in large numbers
in the fluid.
On comparing the luminous plates of Luciola with the light-
giving organs of other Lampyride we are able to compare the clear
cellular elements of the cylindrical lobules, which surround the vertical
tracheal limbs and their branches, with the terminal tracheal cells
described by M. Schultze.
In Luciola the arrangement and distribution of the elements is
much more regular than in other forms, and the plates appear to have
attained to a much higher and more complete grade of development,
as is expressed by the regular structure of the lobes, and by the
special development of the tracheal end-cells, as well as by the constant
dichotomous division of the termination of the trachee.
The author discusses the homodynamy of the luminous organs with
portions of the fat-body, and finds powerful evidence in support of it in
the complete agreement in form, size, and relation to reagents exhibited
by the nuclei of the luminous organs on the one hand, and of the
fat-body on the other. With regard to the loss of substance by
Luciole, Emery’s observations lead to the conclusion that a luminous
and flying specimen loses daily about half a milligram in weight ; it
is to be borne in mind that the imagines eat nothing.
In conclusion, the physiology of the luminous activity is discussed.
The males are either luminous for short and regular periods, or, when
seized or injured, are without intermission, though not so remarkably,
brilliant. In the latter case, which, it is clear, is the only one on
which observations can be made, bright rings are seen on a dark back-
ground, and it would appear that the luminous oxidation takes place
at the surface of, but outside the substance of the parenchymatous
cells. These appear to secrete the luminous material, which is taken
up by the tracheal end-cells, and burnt by means of the oxygen in the
fine branches of the trachew. This combustion can only take place
when the chitinous membrane of the trachee is extraordinarily fine.
The author does not think that this luminous power is a sexual
means of exciting the rare females, but rather that it is a kind of warn-
ing to insectivorous nocturnal animals ; the unpleasant smell which a
Luciola gives off on injury makes it perhaps disagreeable to bats or
other nocturnal animals.
Development of Ccanthus niveus and its parasitic Teleas.*—
H. Ayers finds that the ovum of Ccanthus—the tree-cricket—arises
* Amer. Nat, xviii. (1884) pp. 537-40; from Proc, Boston Soc. Nat. Hist.,
1884, 56 pp. (8 pls.).
Ser, 2.—Von, LV. 2P
554 SUMMARY OF CURRENT RESEARCHES RELATING TO
from a germarium, and not from an ovarian epithelium; and that the
yolk is formed by cell-degeneration and not by secretion. The embryo
exhibits a primitive segmentation, before the appearance of the
permanent segments, each of the seventeen of which bears a pair of
appendages, though some are rudimentary and deciduous. The dorsal
vessel arises as a paired organ, the lateral halves of which give rise, by
fusion, to a median tube, just as in some Vermes; the blood-corpuscles
are the nucleoli of endodermic cells. A rather startling discovery is
that of the gills, which Ayers describes as a pair of lateral outgrowths
derived from the ectoderm of the pleural region of the first abdominal
segment ; the gill-cavities are continuous with the body-cavity, and they
appear to serve as channels through which the vascular fluid circulates.
“The gill-pad is essentially a single-layered sac, with a much-
constricted neck, evaginated from the pleural region of the abdomen ”;
they are not tracheate gills, for they contain no nuclei.
The author failed to observe any sharp distinction between a cell
and its nucleus, or between a nucleus and a nucleolus; but he was
able to detect the existence of segmental enlargements of the meso-
dermic somites, similar to those from which the nephridia of worms
take their origin.
The author discusses the origin and function of the embryonic
membranes (amnion and serosa), and points out that an answer is
impossible if we do not clearly comprehend the relations of the
embryo to its nutriment and food-yolk. They can hardly be supposed
to have been primitively protective in function, and the egg is fur-
nished with a protecting membrane (the chorion) before it leaves the
body of its parent. Ayers comes to the conclusion that the serosa
functions as a yolk-sac, while the amnion is the dorsal wall of the
insect. It is to be noted that in Limulus the serosa does become a
“vicarious chorion ” (Packard), and after the splitting of the true
chorion, forms a protective membrane.
The egg-parasite Teleas appears to be remarkable for the absence
of embryonic membranes, and to give rise to a “ larval form intermediate
between the blastosphere and the cyclops-larva of Ganin.”
Origin of Bees’ Cells.*—Dr. Dénhoff urges objections to the
views of Buffon, carried further by Miillenhoff, that bees’ cells are due
to pressure, pointing out that there is no relation between the forms
of the cells and of the bees’ bodies, and that he has observed a single
female build a nest consisting of a number of six-sided cells; further,
the difference seen in cells formed by bees and drones cannot be
correlated with any differences to be found in the inhabitants; in
the formation of the queens’ cells by other bees there is no pressure
to produce the rhomboid pits; direct observation of the formation
of a comb was not rewarded by any indications of pressure; no
reasonable amount of pressure on the walls of cells seems to have any
effect in altering their form.
The author thinks that Darwin has erred in supposing that the cells
* Arch. f, Anat. u. Physiol., 1884, Physiol. Abth., pp. 153-5.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 555
have at first the forms which they have later on, whereas this is by no
means the case; at first there are nothing but rhomb-shaped spaces,
the size of which is gradually increased.
Closed Poison-glands of Caterpillars.*—Dr. Dimmock states
that if a Cecropia caterpillar “be examined carefully, the black
spines upon its red, blue, and yellow knobs, or tubercles, will be seen
to break easily from the tubercles, and a clear yellow fluid of dis-
agreeable odour to ooze from each opening left by the injury. By
crushing the tubercles with a pair of forceps the same strong odour
is very noticeable, and by this mode of treatment one has no difficulty
in proving that each tubercle, small or large, blue, yellow, or red,
contains the odorous fluid. The red tubercles are seen, in sections
cut with the microtome, to be divided into compartments, the cavities
of each spine opening into a compartment at its basal end. The
spines themselves are quite rigid and very brittle, so that they break
away at a slight touch and leave a hole in the tubercle, out of which
the odorous fluid pours, pushed by internal pressure. This fluid,
which I have not examined carefully, but which I hope later to study
chemically, is strongly acid to litmus paper, but causes a purple pre-
cipitate in carmine solution.” The odour given out by these glands
suggests at once their protective function. Similar glands, i.e. with
no outlet until one is produced by external agency, are not rare in
Bombycid larve. Karsten, in 1848, described the anatomy of the
poison-glands at the base of the hairs of an American Saturnia. The
secretion is ‘‘ perhaps formic acid or a formate in solution.”
Gills of Insect Larve.t—G. Macloskie states that it is usual to
describe the laminz of the pneumatic gills as containing systems of
fine tracheal loops, somewhat after the pattern of a plurality of
carbon-wicks in an Edison lamp. In a specimen, however, of the
rectal branchiew of the larval Libellula, which he rolled under the
cover-glass, he found that the multitude of tracheal ramifications
ended cecally ; all were of about the same length, their extremities
recurved within the containing sac, and their tips not all swollen,
but rounded off. “As they are elastic, and the closing sac disten-
sible, we { think it highly probable that with each water-inspiration
the sacs enlarge and the tracheal spray (having air forced in by the
forward compression of the large trachew) spreads out so as to bring
the full tide of air close to the tide of water. Léon Dufour seems to
have had some process like this in view, when he said that each
lamella of the branchia of Potamophilus ‘is probably swollen during
life by air transmitted by endosmosis. As we understand the case,
the air is injected into the branchiw from the rest of the body by
rhythmical contractions, and its gases then communicate endosmoti-
cally with those in the tidal waters, so as to secure renovation.” The
action of the trachew, Macloskie believes to be tidal rather than due to
peripheral capillary circulation ; there being a flux and reflux, rather
than a mere circulation of the air.
* Psyche, 1882 (4). Amer. Natural., xviii. (1884) p. 535.
+ Psyche, iv. (1883) pp. 110-2. t Amer. Natural., xviii. (1884) pp. 534-5.
2P 2
P
556 SUMMARY OF CURRENT RESEARCHES RELATING TO
Dangers from the Excrement of Flies.*—B. Grassi describes
experiments which show that flies are agents in the diffusion of
infectious maladies, epidemics, and even parasitic diseases.
On a plate on the table of his laboratory he placed a large number
of the eggs of a human Nematode parasite (Trichocephalus). After a
few hours he found, on some white sheets of paper hanging in the
kitchen, the well-known spots produced by the excreta of the flies, and
on a microscopical examination of these spots, several of the eggs of the
parasite were found in them. Some flies coming into the kitchen were
now caught, and their intestinal tract was found quite filled with an
enormous mass of fecal matter, in which the presence of eggs of
Trichocephali were detected. As it was practically impossible to keep
all alimentary substances from contact with these flies, it follows that
the chances of Dr. Grassi and his family being infected with Tricho-
cephali were very great. As a matter of fact, the experiment was
tried with non-segmented eggs of this worm. Another experiment
was in the same direction. Dr. Grassi took the ripe segments of
a Tenia solium (which had been in spirits of wine) and broke
them up in water, so that a great number of the tapeworm’s eggs
remained suspended in the fluid. The flies came to the mixture,
attracted by the sugar, and in about half an hour the ova of the tape-
worms were to be found in their intestines and in the spots. Had
these eggs been in a recent and living state, they would doubtless
have been just as easily transported. To those who care to try these
experiments, it is suggested that lycopod powder mixed with sugar and
water is a good material, as the lycopod spores are easily detected.
It is self-evident that if the mouth-apparatus of the fly will admit
of the introduction of such objects as have been above noted, that there
will be no difficulty in its admitting scores of the spores of many
parasitic fungi, and above all of those belonging to the Schisor: eee
the possible cause of so much disease. Already Dr. Grassi has detected
in fly excrement the spores of Oidiwm lactis, and the spores of ‘a, Botrytis,
this latter taken from the bodies of silkworms dead of muscardine.
There arises, of course, the question of how far the active
digestion of the intestines of the flies may not destroy the vitality of
germs or spores thus taken in, but it would seem probable that in
many instances the larger bodies swallowed may not serve as objects
for assimilation, but may be got rid of as foreign bodies, and it will
be borne in mind that the flies themselves fall victims to the growth
of a parasitic fungus (Empusa musce Cohn), which is probably taken
first into their own stomachs.
8. Myriopoda.
Nerve- terminations on Antenne of Chilognatha.;—A pre-
liminary note upon these structures is contributed by O. Biitschli;
the results were worked out by Dr. B. Sacepine in conjunction with
Dr. Biitschli, but having been left in an incomplete condition, a brief
résumé of the more important new facts seemed desirable.
* Arch. Ital. Biol., iv. (1883). See Nature, xxix. (1884) pp. 482-3.
+ Biol. Centralbl., iv. (1884) pp. 113-6 (2 figs.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 557
Previous observers have noted the occurrence of conspicuous
structures upon the antenue of Chilognatha, which correspond to the
so-called olfactory cylinders of insects recently studied in detail by
Hauser,* and between the two there seems to be a general similarity.
Each of the sensory processes is entered by a nerve which imme-
diately divides into two branches, each covered with ganglionic cells
which are distributed in two groups, the anterior one consisting of
considerably smaller cells than the posterior ones; at the distal
extremity the nerve-fibres again collect into a bundle and form the
termination of the organ; that these fibres are differently constituted
from those which enter the ganglion below is shown by the fact that
their behaviour to staining reagents is different; the sensory process
is often at the free extremity so that a direct communication is
established between these nerve-endings and the outer world.
A structure essentially similar to this is found in Vespa, but is
differently construed by Hauser; according to him the posterior
group of cells is not present since he only figures one nucleus, with
several nucleoli however, while the anterior group of smaller cells has
escaped his attention; accordingly the conclusion to which Hauser
has arrived at is that the whole sensory structure is a single cell;
whereas in reality it consists of a great number of cells.
Ovum of Geophilij—E. G. Balbiani records some observations
made on the development of the germinal vesicle and the follicular
cells of the ovum in Geophilus. In the fresh ovum the germinal vesicle
is spherical; when treated with dilute acetic acid a funnel-shaped
hollow process is seen to arise from the germinal vesicle; one end of
this is in close connection with the germinal spot and a process of the
latter can be observed to penetrate the cavity of the funnel. It is
covered externally by a delicate layer of vitelline protoplasm. In
adult females this “nuclear appendix ” has the form of a long coiled
thread, sometimes it is represented by a number of variously sized
cylindrical masses, at other times by several round bodies scattered
through the substance of the vitellus; the latter conditions are
evidently the result of a division of the coiled thread-like nuclear
appendix, but the division is never complete inasmuch as a considerable
portion always remains adherent to the germinal vesicle. Each of
these small round bodies into which the nuclear appendix splits up
contains all the elements which go to form the ovum, viz. a portion of
the germinal vesicle, the germinal spot, and the vitelline protoplasm.
The wall of the follicle which incloses the ova is seen to contain a
number of small cells which agree in every respect with these small
cellular bodies resulting from the division of the nuclear appendix,
and the view that they originate from the latter is confirmed by the
recent investigations of MM. Fol, Roule, and Sabatier on the ovum of
Ascidians. The follicular cells appear therefore to be the homologues
of the spermatoblasts in the male, and the “ vitelline nucleus ” also
corresponds to one of the same.
* Zeitschy. f. Wiss. Zool., xxxiv. (1880) p. 367.
+ Zool, Anzeig., vi. (1883) pp. 658-62 ch figs. ), 676-80 (3 figs.).
558 SUMMARY OF CURRENT RESEARCHES RELATING TO
y- Arachnida.
Poison Apparatus and Poison of Scorpions.*—J. Joyeux-Laffuie,
from his own studies and a consideration of what has been discovered
by other naturalists, comes to the conclusion that the poison-organ
of the scorpion (S. occitanus) is formed by the sixth or last somite of
the post-abdomen, which terminates by a sharp process, at the ex-
tremity and sides of which are two oval orifices by which the poison
escapes. ‘There are two secreting glands, each of which opens by an
excretory duct to the exterior. Each gland is situated in a cavity,
which it completely fills, and which is formed by the chitinous
skeleton and by an enveloping layer, formed by striated muscular
fibres; it is by the contraction of this latter that the poison is forced
out. The gland has a central cavity which acts as a kind of reservoir,
and a proper wall, which is formed of a layer of cells that send out
prolongations into the cavity, and of a layer of epithelial cells, which,
in the fresh condition, have a finely granulated protoplasm; these are
the secreting cells. The poison is very active, and, even in weak
doses, soon kills most animals, and especially arthropods or verte-
brates. The phenomena of poisoning are always the same, and take
place in the following order—(a) pain at the point of injury;
(6) period of excitement ; (c) period of paralysis. The convulsions
which are characteristic of the second stage, are due to the action of
the poison on the nervous centres, and especially on the brain; the
paralytic phenomena are caused by the action of the poison on the
peripheral extremities of the motor nerves, where they appear to _
have the same influence as curare. The muscles, the heart, and the
' blood are in no way attacked, and the poison may therefore be cer-
tainly placed among those which act on the nervous system. The
scorpions found in France (S. ewropeus and S. occitanus) cannot cause
the death of a human subject, and are only dangerous when several
poison a man at the same time, or attack very young children. To judge
by his bibliography, the author is unacquainted with the observations
on the habits of scorpions, published in 1882 by Prof. Lankester. t
Structure and Function of the Liver of Spiders.{— P. Bertkau
finds that the so-called liver of spiders arises by the develop-
ment of a considerable number of diverticula of different sizes from
the widened portion of that region of the intestine which is found in
the abdomen ; as these branch more and more they become united
into a continuous whole by the formation of an intermediate tissue.
Of the entire diverticula five are larger than the rest, and they are,
like the intestine at their point of origin, glandular in nature. The
epithelial cells are either small and oviform, closely packed with
large colourless spheres, or they are larger and club-shaped, when
part of their contents consists of small crystals and larger drops,
which are yellow, brown, or green in colour. The chief function of
the secretion of these glandular cells is the breaking up and altera-
* Arch. Zool. Expér. et Gén., i. (1883) pp. 733-83 (1 pl.).
+ See this Journal, ii. (1882) p. 612.
} Arch. f. Mikr. Anat., xxiii, (1884) pp. 214-45 (1 pl.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 559
tion of fibrin and other albuminous bodies. Spiders do not take in
food in the solid form; they dissolve the muscles, &c., of their prey,
and suck in the fluid food; this passes into the final branches of the
enteric diverticula.
The hind-gut commences just behind the last pair of these diver-
ticula. The Malpighian vessels ramify in the intermediate tissue,
and secrete guanin or an allied substance. This body may be found
deposited in the outer layer of the intermediate tissue, and it takes a
considerable share in the coloration and marking of the animal.
On the whole, it would be well, in the present state of our knowledge,
to substitute for the name “liver” that of “ chyle-stomach.”
In the substance of the organ itself we may distinguish more or
less regular hemispheres of various shades, an almost completely
transparent tissue, and a system of fine richly branched Malpighian
canals ; these last have fine canals which pass into wider collecting
ducts, which open into a wide cloaca; the walls of this have a distinct
muscular investment, formed by an outer layer of longitudinally
and an inner of transversely disposed fibres.
The author gives some account of the differences which the
cxcal diverticula present in various genera of spiders and in forms
allied to them.
Anatomy of Acarina-*—J. MacLeod, in a preliminary notice,
states that, in his investigation of the Acarina, he has made use of
sections, after hardening in picrosulphuric acid or alcohol, and stain-
ing with carmine, but that the successful results seem to have been
greatly due to chance, specimens collected at the same time and
treated in exactly the same way behaving very differently on treat-
ment with hardening and staining reagents. The genera examined
were Trombidium, Argas, Hydrachna, and Gamasus.
He finds that the tracheiform excretory ducts of the salivary
glands open separately into the labial groove at a short distance in
front of the buccal orifice. The description given by Henking as to
the presence of short narrow ducts arising from tubular glands is
confirmed. The suctorial apparatus of Argas differs completely from
that of Trombidium, accurately described by Henking ; it has three
branches, each of which is bifurcated, and is provided with three
radiating muscles. Notwithstanding the difference in their structure
the two organs seem to obey the same dynamical laws.
The author has been able to definitely assure himself of the com-
munication between the stomach and the terminal intestine, which,
denied by most authors, has only been regarded by Henking as pro-
bable on 4 priori grounds. The communication is effected by a pair of
lateral orifices, which are extremely narrow, and have their lips almost
always closely applied to one another; the difficulty of detecting them
is increased by the presence of a large number of almost villiform
cells which are found around them.
The terminal intestine is filled by a granular substance, which is
composed of brownish-yellow granulations similar to those that are
* Bull. Acad. R. Sci. Belg., lviii, (1884) pp. 253-9, :
560 SUMMARY OF CURRENT RESEARCHES RELATING TO
found in the stomach, and which are probably the true excreta; and
of much larger granulations formed of concentric layers, which seem
to be true calculi, which are formed not in the intestine, but in tubes
which open into it, and in which similar calculi are to be found.
These tubes appear to be Malpighian; but the chemical examination
of the calculi is still to be effected.
In conclusion, MacLeod throws great doubts on the exactness of
the descriptions of the skeletal part of Acarina as given by previous
writers, and promises to enter more fully into this subject.
6. Crustacea.
Sexual Colour-Variation in Crustacea.*—Differences in the
colour of the two sexes among Crustacea are of very rare occurrence.
Darwin in ‘ The Descent of Man,’ chap. ix., says he is acquainted with
but two instances of this peculiarity: one in the case of Squilla
stylifera, and a second in a species of Gelasmus, or fiddler crab. H.
W. Conn records a third and very striking instance in Callinectes
(Neptunus) hastata, the common edible crab of the southern coast of
North America. There are a number of differences in the shape of
the two sexes, but besides these they present a marked difference in
colour. This colour-variation is confined to the first pair of thoracic
appendages, the pair bearing the large chele. These appendages
are of a yellowish brown on the upper surface, a whitish yellow on
the outside, and of a brilliant blue on the inside and particularly at
those parts which are protected from the light when the appendage is
folded. It would seem therefore that this blue coloration was en-
hanced by not being exposed to light. The colour of different
individuals is tolerably constant and uniform.
Between the colours of the male and female appendage considerable
differences are discernible. The most noticeable difference is that
the male appendage appears remarkably blue when compared with the
female. This is due partly to the fact that the amount of blue surface
in the male is much greater than in the female, and partly to the fact
that the blue colour is of a much more brilliant hue. The blue
colour in the male extends nearly to the tips of the two fingers of the
chele, both the finger-like process of the propodite and the dacty-
lopodite being largely coloured blue. The extreme tips are, however,
of a brilliant purple. In the female these parts are of an orange hue,
with not a trace of blue about them. Its tips are also coloured
purple, but not so brilliant a purple as is found in the male. In the
male the blue colour extends partly upon the outer surface. In the
female it is confined to the inner surface and only extends to the base
of the dactylopodite. The outer surface of the dactylopodite and of
the finger-like process of the propodite are in the male white, while
in the female they are reddish orange. Upon the male appendage
there is no orange colour as a rule.
These differences in colour are in all cases very marked, and will
always serve to distinguish a male from a female appendage. No
' Johns-Hopkins University Circulars, ili, (1883) p. 5.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 561
colour differences are seen in any part of the crab except upon the
first pair of appendages, and it is interesting to note that this sexual
difference does not make its appearance till the crab reaches maturity.
The chele of immature males and females cannot be distinguished
from each other. Fritz Miiller says that the same is true of the
Gelasmus species observed by him. On the other hand, considering
the habits of Crustacea, these sexual differences can hardly be
considered as the results of sexual selection.
Observations on Tanais cerstedi.*—H. Blanc takes Tanais as his
text for a study of the characters of the heteropodous Asellidz. Com-
mencing with a general account of the body and its appendages, he
states that the differences between the cephalothorax of the male and
female are not so well marked in young examples, and are not at all
apparent in embryos. In old specimens the chitinous integument is
incrusted with calcareous salts, which have the form of small masses,
crystalline in structure, which may be either needle-shaped or rounded.
The concretions are altogether similar to those found by Hoek in the
Caprellidz, and the differences in their form are due to the presence
or absence of a hypodermic nucleus. The tegumentary glands
are represented by three pairs of large glands which are placed
beneath the lateral integument of the first three free segments of
the thorax, and by twelve pairs of glands, which are much smaller
than the others and are placed in the lateral portions of all the
thoracic and abdominal segments, and in the head. The former
are racemose in structure and closely resemble the same organs
in Phronima, Hyperia, and Corophium. Each element of the racemose
glands is formed of a mass of protoplasm, which contains two
very clear nuclear vesicles, each of which is nucleolated. Each
vesicle is, therefore, formed of two cells. The secretion from these
cells passes out by small unbranched canaliculi, to reach the exterior by
a single canal. The large thoracic glands are best developed in
females carrying embryos in their incubatory pouches, and in them
the glandular elements have their protoplasm almost entirely converted
into a secretion. The product secreted hardens in the water and so
forms a tube into which the Tanais may retreat ; when fresh, and to the
naked eye, this secretion appears to be filamentous ; but when examined
under the Microscope, it is seen to be composed of small rod-shaped
corpuscles similar to those contained in the glandular elements. The
secretion is more colloid than mucilaginous, for it does not coagulate
with alcohol or form an emulsion with olive-oil. The secretion of the
smaller pyriform glands probably has the function of secreting a
product which prevents the animal from drying completely when it
happens to float on the surface of the water.
The supra-cesophageal mass is elongated in the male, and short,
widened out laterally in the female. It is distinctly divided into a
superior optic portion and an inferiorly placed part which is larger
and forms the true cerebrum. The differences between the supra-
cesophageal ganglia of the male and female are carefully pointed out.
* Recueil Zool. Suisse, i. (1884) pp. 189-258 (3 pls.).
562 SUMMARY OF CURRENT RESEARCHES RELATING TO —
The arrangement of the nerve-cells in the ganglia of the ganglionic
cord, as well as the double nature of the commissures which unite
them, prove that the chain has arisen phylogenetically from two lateral
nerve-cords. The whole nervous system of Tanais has a greater
resemblance to that of the Isopoda than of the Amphipoda; the
reasons for this statement are fully given.
After many vain inquiries the author was at last able to observe
in a young specimen the presence in the auditory vesicle of very fine
and very short hairs, which were arranged in a single row on a small
part of its inner surface ; no nerve could, however, be detected. Only
twelve crystalline cones were found in the eye, and these were very
short, and all of the same dimensions.
The muscles of the body and the appendages were arranged in
the manner usual among the Isopoda. The fatty body completely
surrounds both the dorsal and ventral faces of the intestine ; below it
also surrounds the ventral ganglionic chain and forms the so-called
external neurilemma. In the abdomen, where it is most abundant, it
forms two large masses on either side of the intestine. Itseems to be
more abundant in young than in old animals; in old specimens it
disappears altogether, so that it seems to play an important part in
the nutrient functions of the animal, and in the development of the
body and its organs. The adult males take no food.
Respiration, in addition to being performed in the manner common
among Decapods, is, as in Isopods, also abdominal. After a full
description of the anatomy and physiology of the circulatory organs
and of the digestive apparatus, in the course of which it is pointed out
that the masticating stomach of the female is more complicated than
that of the male, Blane passes to the renal organs; the seat of the
urinary secretion is the fatty body, and the products of secretion are
deposited more or less largely along the intestine; they are yellowish
in colour and have the form of agglomerated masses of small rounded
or angular corpuscles. Chemical investigations have demonstrated
the uric nature of their deposits, and observation has shown that they
are more abundant in old than in young examples.
After some observations, not so complete as the author wished, on
the sexual organs and on the “biology” of Tanais, Blanc discusses
the question of whether they are Amphipods or Isopods; the balance
of evidence seemed to him to be in favour of the latter, and to justify
Milne-Edwards’ establishment of a group of ‘“‘ Asellotes hétéropodes.”
As to whether Tanais is the ancestral form of the Isopods, as some
have thought, it is necessary to be very careful, but, at the same time,
one cannot fail to see such resemblances between Tanais and the
zoéa-stage of Decapods as is represented by the mode of branchial
respiration, the absence of abdominal appendages in the embryonic
Tanais, and the possession of eyes placed on short stalks, and of an
auditory vesicle which is open to the exterior.
New and Rare French Crustacea.*—In his 33rd article under
this title M. Hesse deals with several new parasitic Crustacea
* Ann. Sci. Nat.—Zool., xv. (1883) art. No. 3, 48 pp. (3 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 563
belonging to the order of the Siphonostomata, and especially to the
Pelticephalidz, of the genera Nogagus, Lepimacrus (nov. gen.),
Pandarus, and Cecrops ; all of these have been described and figured
from living examples; they all live on fishes with an extremely thick
skin, the scales of which are so closely arranged as to render
penetration extremely difficult, and they all have a very special form
of buccal apparatus, consisting of a rigid tube which is narrowed at
its extremity, and which is deeply plunged into the flesh of the host
so as to draw from it the fluids necessary for food. The fishes are
all members of the group of the Squalide.
After a full description of Nogagus spinacii (N. achantias), we have
an account of an attached embryo; the latter was 3 mm. long by 1
wide ; it was provided anteriorly with an umbilical process which
served as an organ of attachment, but was so flexible as to be able to
be turned in various directions ; on either side. of this were a pair of
long flattened antennz formed of two joints, at the end of which were
several divergent hairs. The eyes were relatively large and not
widely separated from one another. The body was tubular in form
and consisted of five rings, the first of which served as the point of
attachment, ‘These embryos were very active and lively, and on several
occasions were seen to be living, even when the Crustacea to which
they were attached were far gone in the way of decomposition.
The new genus Lepimacrus is founded on a single female specimen
found on Lamna cornubica; the species is called L. jourdanii.
Several species of Pandarus and one of Cecrops are next described ;
and this is followed by some notes on their “ physiology ” and “ bio-
logy.” It is pointed out that the mucilaginous tegumentary secretions
of the piscine hosts render the skin more supple and more easily
penetrable by the organs which attempt to perforate them. When
deprived of this advantage and incompletely fixed to a thick and
coriaceous envelope they easily fall off when the fish is captured and
withdrawn from the water, and are then difficult to find.* The para-
_ sites of the Squalide may be seen to select the thinnest parts of the
skin, such as the axille or the eyes. Scyllium canicula, catulus, and
annulatus have never been found to be infested with parasites, and it is
a significant fact that their skin is very thick.
Hesse is of opinion that Nogagus should be placed with the Pan-
darine rather than the Caligine: and has some remarks on the term
Siphonostomata, which has been rightly applied to those Crustacea,
which, like the Pandarina, have a special syphonate buccal apparatus,
by means of which they are able, after having pierced the skin of the
fishes upon which they live, to penetrate their flesh and draw thence
their nutriment ; this apparatus is not, however, found in Argulus, or
Caligus, which are ordinarily associated with them, (It may be
observed that one of the best authorities on the Copepoda—Professor
Claus—makes a special division—that of the Branchiura—for Argulus.)
The forms just mentioned bite rather than prick. For the Argulina
* It may be pointed out, in this connection, that the number of parasitic
Copepods collected by the ‘ Challenger’ was very small,
564 SUMMARY OF CURRENT RESEARCHES RELATING TO
and Caligina the author proposes the term of Rostrostomata —to which
there is the obvious objection that it is a vow hybrida. ‘The author
gives a table to show the systematic changes which he proposes.
Vermes.
Nervous System of Euniceide.*—G. Pruvot finds in Hyalinecia
tubicola that the two central ganglia are so curved and connected
by a thick median commissure that there is superiorly a “ ventricle ”
which communicates by a large anterior cleft with thé general cavity.
In the family generally we find that the cerebroid mass is made up of
two distinct parts, one cerebral and one stomatogastric; the antennze
and the organs of sense are innervated exclusively by the posterior
or cerebroid portion of the mass; the unpaired posterior appendage
represents a pair of appendages fused along the middle line. The
stomatogastric centre alone provides the nerves of the palpi and the
stomatogastric filaments, and the whole system presents essentially
just the same arrangement as the general nervous system, for there
is a supra-cesophageal centre, an cesophageal collar, and a ventral
chain of, at least, two ganglia, the lower of which appears to the
author to be constricted and to be formed by the fusion of what were
primitively two ganglionic masses.
Cerebrum of Eunice harassii, and its relations to the Hypo-
dermis.}|—E. Jourdan describes the cerebral ganglia of Eunice harassit
as being composed of a central mass of dotted substance, which is
covered by a thick layer of nervous cells (the nuclear layer of
Ehlers). Above this, and just below the cuticle, there are epithelial
elements whieh are conical in form, and have their bases, instead of
terminating on a membrane, prolonged into rigid filaments, which
penetrate into the nuclear layer, and, by uniting, give rise to, as it
were, pillars which pass from the cuticle to the mass of dotted
substance. The protoplasm of these hypodermic cells is greatly
reduced, and their nuclei are characteristically fusiform. They
become lost in the nuclear layer, and closely fused with other fibrils,
which have a similar histological character, but are of a different
origin.
The nuclear layer, which is rightly regarded as being nervous
in nature, is made up of various elements. In section the layer forms
a delicate plexus between the hypodermic pillars, and each of the
spaces is occupied by a spherical nucleus. 'The nerve-cells of the
layer are composed of a large nucleus, hardly any protoplasm, and
a fine enveloping membrane; they give off one or two processes,
which are exceedingly delicate when taken singly.
The fibrils which are connected with them, but which, as has been
already said, are of different origin, arise from the nerve-cells ; though
their function is no doubt different to that of the hypodermic fibrils
their histology is absolutely the same. The spaces left in the
* Comptes Rendus, xcviii. (1884) pp. 1492-5.
t Ibid., pp. 1292-4.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 565
reticulum are filled by a fine protoplasm, which is perhaps comparable
to the granular substance of the neuroglia of Vertebrates.
The close relation between the hypodermic epithelial cells and
their prolongations with their nerve cells and fibres, together with
the absence of any histological differences between the two sets of
fibrils, are especially interesting as calling to mind the characters of
the nervous system of larval Annelids.
Varieties of Branchiobdella varians.*—W. Voigt has a careful
study on the variations of B. varians.
He finds that we have here to do with an animal which may
be of great importance in our knowledge of the mode of origin
of species. He shows that it is on the very point of giving rise
by its varieties to new species. The so-called B. parasita is
undoubtedly the form from which the others have been derived. The
fact that the variety hewodonta found on the gills of crayfishes in
North Germany is replaced in South Germany by the variety astaci
points to external influences as being the cause of this local dis-
tribution ; the differences may be supposed to be due to temperature
or to the qualities of the water, or the bodies dissolved therein. To
such suppositions there are, however, powerful objections, and we
must therefore look for the causes of variation in the animals them-
selves. Differences have been observed in the size of the ova, and in
the characters of the dissepiments between the segments which carry
the segmental products; with these other differences appear to be
correlated, but their exact relations have as yet to be carefully
worked out.
Ovum and its Fertilization (in Ascaris).{—The discrepancies in
the recorded observations of fertilization in the ova of Echinoderms
led E, van Beneden to study the subject in fresh types, and finally to
pursue in the Ascaris megalocephala of the horse the important series
of observations which he has recently published in great detail.
The memoir is divided into four descriptive chapters and a general
summary.
The first chapter describes the constitution of the ovum and
spermatozoon.
The advantage to be obtained from studying the ovum in this
Nematode is that in the uterus and oviduct definite stages of fertiliza-
tion constantly occur at definite points.
On quitting the ovarian rachis the previously bilateral ovum
acquires an elliptic form, and—at the point of previous attachment
—shows a micropyle, underlying which is a naked protoplasmic
process, the plug of impregnation, situated on a polar disk forming a
slight eminence on the transverse (or short) axis of the ellipsoid.
Ultimately a delicate membrane comes to cover the ovum except at
the micropyle. Within the so-called “nucleus,” or germinal vesicle
(which is bounded by a membrane), is the “nucleolus,” or germinal
corpuscle, consisting of two disks and situated peripherally on the
* Arbeit. Zool. Inst. Wiirzburg, vii. (1884) pp. 41-94 (2 pls.).
+ Arch, de Viol., iy. (1883) pp. 265-640 (1 pl.),
566 SUMMARY OF CURRENT RESEARCHES RELATING TO
prothyalosome, a differentiated, and slightly elevated, portion of the
nuclear mass.
Within the uterus of the fertilized female the zoosperms occur _
in four forms, marking four stages of development, though all are
capable of fertilization. xcept in the first, or simply amceboid,
stage, each zoosperm consists of a granular, nucleated, cephalic hemi-
sphere, and of a caudal process containing a refringent body and fibrils
of a contractile nature. A definite membrane surrounds the “ tail ”
of the zoosperm, ending with a free border at the neck, and not
investing the naked protoplasm of the cephalic hemisphere.
The second chapter deals with the penetration of the zoosperm
into the ovum,i.e. with “ the copulation of the sexual products.” On
this subject Van Beneden has observed that, in Nematodes, as a
general rule, only one zoosperm penetrates an ovum. The erroneous
view that many zoosperms entered to fertilize a single ovum, is due to
the presence of certain refringent bodies in the vitellus. (In Mam-
mals, where many zoosperms commonly penetrate an ovum, one only
effects fertilization, the others being assimilated as food.) The zoo-
sperm always enters at the micropyle, round which the membrane of
the ovum rises up to form a “perivitelline space.” On entering, the
zoosperm applies itself to the “ plug of impregnation ” by its cephalic
hemisphere,—its axis being thus applied in continuation of the
embryonic axis of the ovum, and the homologous regions of the two
elements being thus brought into contact.
Aided by its own amceboid movements, the zoosperm is now borne
into the ovum centripetally by the protoplasmic process to which it
is applied. ‘The membrane of the zoosperm enters into intimate
relations with the egg-membrane, finally fusing with it to form a
continuous ovo-spermatic membrane.
In his third chapter, Van Beneden deals with the “modifications
which take place in the ovum from the time of copulation of the
sexual products to the time when the unification of the mature ovum
and zoosperm commences.”
In Ascaris megalocephala a Upsiliform figure represents the first
“ directive spindle” of Biitschli (Fol’s first “‘amphiaster de rebut”).
This characteristic figure consists mainly of achromatic fibrils, with
two chromatic disks, lying in a clear body (representing the prothya-
losome) at the junction of the three limbs of the Upsilon. The
chromatic elements are derived from the germinal corpuscle, the
achromatic fibrils from the germinal vesicle and its membrane.
As the zoosperm reaches the centre of the ovum, the vertical
limb of the Upsilon becomes connected with it by filaments (probably
muscular in function), and the figure becomes T-shaped, the trans-
verse limb taking on the appearance of a spindle. Meantime the
vitellus loses all traces of its radiate structure, becoming granular
throughout.
“The first polar body is now formed at the expense of the reduced
prothyalosome and of the chromatic elements it contains. Hach of the
two chromatic disks furnishes to the polar body the half of its sub-
stance, and the prothyalosome divides tangentially. The elimination
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 567
is not of a pole of the spindle, but takes place in the equatorial
plane.”
In the vitellus a homogeneous perivitelline layer is differentiated
peripherally, and the refringent body in the caudal portion of the
zoosperm is ejected into the perivitelline space. In spite of the
striking analogies, the genesis of the first polar body is not to be
compared to indirect cell-division.
After the elimination of the first polar body there remains an
homologous body, the deuthyalosome. This latter body increases in
size at the expense of the vitellus and developes two “ asters” on its
surface, one peripheral, the other central. Complicated pseudo-karyo-
kinetic figures are now formed, but disappear before the elimination of
the second polar body, which is formed from the deuthyalosome much
in the same way as the first polar body from the prothyalosome, and
apparently at the same spot on the ovum. A second perivitelline
layer is now formed. The second polar body (i.) is the equivalent of
the female pronucleus which remains behind, and (ii.) cannot be
regarded as a cell.
So far, Van Beneden concludes, no phenomena of true fertilization
have occurred, merely “‘ phenomena of the maturation of the ovum.”
The formation of the pronuclei and the true phenomena of fertili-
zation are treated in the fourth chapter. The female pronucleus (the
equivalent of the second polar body) consists of chromatic and
achromatic elements, derived from the germinal corpuscle and the
prothyalosome respectively. Contemporaneously with the expulsion
of the second polar body, the male pronucleus is formed, exclusively
from the nucleus of the zoosperm. Ultimately the two similar pro-
nuclei meet in the centre of the reduced ovum (or female gonocyte, as
it is now termed), and unite partially without fusion. A single
dicentric karyokinetic figure is now formed (derived equally from the
two pronuclei), and segmentation begins.
“The egg, furnished with its two pronuclei, behaves like a single
cell, and the sum of the two nuclear elements is equivalent to a
simple nucleus. The first cell of the embryo is accordingly formed
from the moment when the two pronuclei are fully developed ; fertili-
zation coincides with the genesis of the two pronuclei.”
Van Beneden concludes that “fertilization consists essentially in
the formation of the female gonocyte, and its transformation into a
cell, that is to say, in the replacement of the expelled elements by
the new elements introduced by the zoosperm. The polar bodies are
replaced by the male pronucleus.”
All cells of the tissues are thus hermaphrodite, and fertilization
is not a generation but merely a substitution requisite for the in-
definite conservation of life.
Spermatogenesis in Ascaris megalocephala.*—We have yet
another contribution to our knowledge of the development of sperma-
tozoa, from E. van Benedenand ©. Julin. The Nematodes in general
and Ascaris megalocephala in particular lend themselves remark-
* Bull. Acad. R. Sci. Belg., vii. (1884) pp, 312-42.
568 SUMMARY OF CURRENT RESEARCHES RELATING TO
ably to a study of the successive phases in the development of the
spermatozoa, not only on account of the comparatively large size of the
spermatozoa, but also because of the simple and typical arrangement
of the male apparatus, which is formed by a single tube whose
diameter insensibly increases in size from the blind end to the orifice.
The best method of investigation is to use the double means of first
examining successively dissected portions of the seminal tube, and of
making a series of sections of a tube first hardened and properly
stained. If we wish to avoid the errors into which preceding
writers have fallen, we must be very careful to neglect no part of the
tube. The later authors, such as Schneider, Nussbaum, and Hallez
have, further, committed the fault of neglecting the bibliography of
the question, and especially the excellent work of Munk published as
long ago as 1858.
The authors proceed to a description of the several parts of the
male tube—testicle, efferent canal, seminal vesicle, and ejaculatory
canal. They describe then in detail and sum up their results in the
following terms :
It is necessary, in the history of spermatogenesis, to carefully
distinguish between the formation of the spermatogonia at the
expense of the spermatomeres, and the division of spermatogonia into
spermatocytes. The multiplication of spermatogonia appears to be
effected, in A. megalocephala, directly and not by karyokinesis,
while the spermatocytes arise by the indirect or karyokinetic division
of the spermatogonia. The karyokinesis presents some special
characters; the typical form of the chromatic cord is replaced by a
rod-shaped form, and the primary loops have the shape of truncated
cones. The longitudinal division of the primary loops results from
the appearance of a circular vacuole in each of the pyramids; this
vacuole extends to the equatorial plane, and brings about the division
of the pyramid into two quadrilateral plates, which represent the
secondary loops. ‘The polar corpuscles which occupy the centre of the
attractive spheres are remarkable for their affinity for colouring matter.
The asters may be distinctly seen to be the cause of the temporary
division of the cell into three portions, separated by circular con-
strictions.
In the region where the spermatogonia are formed at the expense
of the spermatomeres there are to be observed, between the cells,
corpuscles which have a close resemblance to polar globules ; these the
authors call residual globules. They appear to have been expelled
by the spermatomeres after the karyokinetic metamorphosis, and the
expulsion seems to be effected in the equatorial plane of the dicentric
figure, as in the case of the polar globules. If this account be
correct, the residual corpuscles are comparable to the polar globules
of the egg.
The spermatocyte, before becoming a spermatozoon, gives off a
portion of its substance, which belongs to the cytophoral part; the
formation of the cytophore is in no way comparable to a cell-division.
Just as the egg, when completely matured, is a cell reduced to that
which Van Beneden has called a female gonocyte, so is the spermatozoon
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ” 569
a reduced cell. 'The reduction is accomplished in two distinct stages
of development ; first affecting the spermatomeres, and then the sper-
matogems. While each spermatocyte intervenes in the formation of
a eytophor, the residual corpuscles are formed by the spermatomeres,
in such a way that not only each spermatocyte (and, therefore, each
spermatozoon), but also each spermatogon only possesses a reduced
nucleus.
Spermatogenesis in Ascaris megalocephala.*—P. Hallez, like
E. van Beneden, has selected this convenient Nematode for the study
of the phenomena of spermatogenesis. After a short description of
the male organs, he points out that young of different ages as well as
mature specimens must be examined. The spermatospores, which are
formed at the blind end of the seminal tube, consist of a homogeneous
extremely transparent protoplasm ; by division into four the nucleus
gives rise to four protospermatoblasts, which form protospermatogems.
The former give rise to a (second) generation of deutospermatogems,
which are formed by a large number of deutospermatoblasts. The
last become isolated, and consist of a homogeneous protoplasm and a
nucleus which is deeply stained by reagents. As they increase in
size their protoplasm becomes finely, then more distinctly granular,
while the nucleus grows larger and developes a nucleolus.
When they have reached a size of about 18 in diameter they
divide by nuclear division; and this division is effected at about
440 mm. from the blind end of the seminal tube.
The deutospermatoblasts now become filled with refractive
granules, and soon exhibit a phenomenon which has not yet been
observed in the animal kingdom. They undergo conjugation by
pairs, and the two become closely united with one another. The
nuclei, after fusion, separate afresh. As they tend to separate from
one another each gives rise to corpuscles, which resemble polar
globules.
The further development of the separated and ejaculated deuto-
spermatoblasts must be made out in the organs of the female; when
they first enter the ducts they are spherical cells, 18 or 19 w in
diameter, their protoplasm is filled with refractive granules, and they
have a nucleus which can be easily stained. After a certain time the
refractive or nutrient granules disappear, and the deutospermato-
blasts appear almost to be amceboid in character. They are now con-
verted into spermatozoa, which are ordinarily conical or pyramidal in
form; the nucleus is constantly found outside the spermatozoon,
The fertilizing element is now ripe and may be seen to apply itself
to and fecundate an ovum.
Nematoids of Sheep’s Lungs.}—F. Karsch has a notice of A. Koch’s
essay on the Nematodes of sheep’s lungs, in which especial attention
has been given to Strongylus rufescens and its developmental history.
The author found in the lungs of a Hungarian race of sheep a
number of hair-like microscopic parasites which he regarded as new
* Bull. Sci. Dép. Nord, vi. (1883) pp. 132-5.
+ Biol, Centralbl., iv, (1884) pp. 51-3,
Ser. 2—Vor, LY. 2 a
570 SUMMARY OF CURRENT RESEARCHES RELATING TO
and to which he applied the name of Pseudalius ovis-pulmonalis. The
males are brown, the females milky white in colour; the latter lays
its eggs in the finest branches of the bronchi, and the pulmonary
alveoli; the young escape by the trachea, and the sexually mature
forms enter by the same passage. The young make their way into
mud or water, and thence pass first of all inio the stomach of the
sheep; to return again to the gullet and so to get into the larynx.
The author believes that he has here to do with a diminutive form of
S. rufescens, which, by constantly living in the finest terminations of
the bronchi, has accommodated itself to the diminishing calibre of
these vessels.
Free-living Nematodes.*—Up to the present the free-living
Nematodes have received comparatively little attention ; absolutely
nothing is known abont the exotic forms, and but few notices have
been published of the forms that occur in Europe. In England
Dr. Bastian has published an elaborate memoir of the free-swimming
Nematodes, chiefiy the marine forms; while on the Continent Eberth,
Schneider, Marion, and Biitschli have contributed largely to our
knowledge of the group. The Monograph of De Man deals exclusively
with those species that are found in the Netherlands. The work is
divided into two parts, a general and a systematic ; in the first is treated
the history of the group, their organization, mode of life, capture,
methods of preparation, and their geographical and seasonal distribu-
tion in the Netherlands. The second half contains a description of _
all the species found in the Netherlands, as well as a noiice of all
the free-living species that have been described, with references to the
published descriptions. The text concludes with two tables showing
the distribution in the Netherlands of the different species, and a
classification of the species according to the size of the body. The
Monograph is illustrated by thirty-four plates.
Trichina and Trichinosis.}|—This work is the result of a duty
intrusted to J. Chatin by the French Government, who desired exact
information as to the character of the preserved meats imported from
America. The author concludes that“ in the name of public hygiene,
as well as in that of agricultural interests, public opinion demands a
careful examination of all animals that enter the country, whether
they be alive or dead.” But he points out that it is for the legislator
to prescribe the measures which are necessary for preserving the
public health, and that the business of the naturalist is concluded
when he has investigated the history and development of the parasite,
and has drawn from these conclusions as to prophylactic methods.
The work is one which should be known to all who are engaged in
either the physical or legislative problems which surround the ques-
tion of diseased meats.
* «Die frei in der reinen Erde und im siissen Wasser lebenden Nemaioden der
niederlandischen Fauna.’ Leiden, 1884, 34 pls. Cf. Biol. Centralbl. iv. (1884)
pp. 191-2.
7 ‘La Trichine et la Trichinose” Paris, 1883, 8vo, 257 pp. (15 pls).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 571
Cystic Stages of Teniade.*—A. Villot finds, as a result of pro-
longed inquiries into the characters of the cystic stages of Tape-
worms that the mode of formation of the head is identical in all
species, genera, and types. The true head, the future scolex, never
proceeds directly from the candal vesicle ; it is always separated from
it by an intermediate portion, which he has called the body, and
which forms its immediate envelope. Tho differential characters
which can be drawn from the modifications in structure and develop-
ment have only a secondary value and cannot be used as the basis of
a natural classification. In the next place, it is to be observed that,
contrary to what is ordinarily taught, the caudal vesicle of the cysti-
cerci may be formed in different ways; these differences have a future
morphological importance. Cysticerci are either cysticerci properly
so called, or are cysticercoids; the latter may be grouped under two
heads and subdivided into six entirely new genera. The first section
consists of those in which the caudal vesicle is formed by endogenous
gemmation, and here we have Polycercus for the form found by
Metschnikoff in Lumbricus terrestris, Monocercus for the so-called
Cysticercus arionis ; in the second section, or that of those in which
the caudal vesicle is formed by exogenous budding, we have Cercocystis
for the form found in the larva of Tenebrio molitor, Staphylocystis for
S. bilarius and S. micracanthus, Urocystis for a form found in Glomeris,
and Cryptocystis for the curious form found by Metschnikoff in the
visceral cavity of Trichodectes canis.
The forms that are the most ancient and most closely approximated
to the primitive type appear to be those that belong to the genera
Urocystis and Cryptocystis ; it is in these that we observe the greatest
independence between the different stages of development; the
proscolex, cystic, and scolex-stages are perfectly distinct; the first,
after having budded off the caudal vesicle separates from it, 80 soon
as it has attained maturity, and no part of the proscolex is found in
the perfect cysticercus. In Staphylocystis and Cercocystis the caudal
vesicle adheres to the blastogen, but has only the function of a
support or simple appendage. In the first section of the cysticer-
coids the blastogen not only persists, but forms a permanent envelope.
In passing from the cysticercoids to the true cysticerci we advance
another stage in the scale of differentiation, and, at the same time, note
a remarkable abbreviation in the history of development, for the stage
represented by the budding of the caudal vesicle is entirely sup-
pressed. This “serial co-ordination” of the cystic stages may be
expressed by the simple law that the most differentiated types of
organization have their development the most condensed ; those that are
relatively lower are more diffused ; in other words, the complication of
development and of organization are in inverse relation to one another,
Anatomy and Development of Trematoda.{t—J. Bichringer devotes
the greater part of this essay to sporocyst-stages, and has investi-
gated the characters of Cercaria armata, C. macrocerca, CU. micrura,
* Aun. Sci, Nat,—Zool., xv. (1883) art. No, 4, 61 pp. (1 pl.).
t Arbeit. Zoul, Inet, Wiirzburg, vii. (1884) pp. 1-28 (1 pl.).
202
572 SUMMARY OF CURRENT RESEARCHES RELATING TO
Bucephalus polymorphus, Cercaria acerca n. sp. (found in various
organs of Onchidiwm carpenteri), and another sporocyst from a species
of Onchidium from Singapore.
In describing the structure of the sporocysts, he deals with the
epidermis, and points out that the so-called cuticle is not truly a cuticle,
but is a membrane in which a varying number of nuclei are to be detected;
its development is difficult to follow, but it would seem to be due to the
fusion by peripheral growth of some of the outer cells of the gastrula,
and to be comparable, therefore, to the ectoblast of the first order,
which has been described by Schauinsland in the embryos of Trema-
todes, and to the embryonic investment of Teenie, as described by E.
van Beneden. On the whole, we are justified in regarding it as an
epidermis and comparing it with the “ hypodermis” of other worms.
The muscular layer is always very thin, and its outer layer consists
of delicate, closely applied, circular fibres; below these is a longi-
tudinal layer, which is often much less distinct. Cercaria macro-
cerca is remarkable for having them broader and more distinct from
one another than they are in other forms.
The germinal epithelium is in most cases unilaminate, and varies
in form in different species, the cells being cylindrical, cubical, or
flattened. OC. macrocerca is here again remarkable for having large
clear cells, which may be set in one or several layers, On their distal
side there are nuclei, which lie in a protoplasmic fundamental substance,
and which in section appears to form an anastomosing plexus.
The so-called paletot is a fourth layer which is often present, and
which, in the opinion of Leuckart, is due not to the guest but to the
host; and the author is of opinion that the substratum from which it
arises is the blood of the host, while the elements of which it is
composed are the cells of the snail’s blood. After discussing this
question at some length Biehringer passes on to the sucker or depres-
sion which is often found at one pole of a sporocyst; its structure
agrees so completely with that of the rest of the body-wall that it may
be considered as a mere invagination of the whole sac. Jt no doubt
serves as an organ of attachment.
In dealing with the formation of the germinal bodies, and beginning
by discussing the views of previous writers, and especially of Leuckart
and A. P. Thomas, with the latter of whom he is in complete.agree-
ment, he tells us that he is led by his own observations to think that
the developmental cycle of the Trematoda is a real case of alternation
of generation.
Tn conclusion there are some remarks on the influence which the
gradually developing brood exercises on the organization and activity
of the sporocysts. When the brood remains at a lower grade of deve-
lopment the nurse contrives to grow; later on, when the daughter
generation is undergoing further development, it suffers a passive
extension, but this does not equally affect the whole of the body of
the nurse, but depends on the number and size of the germinal bodies
which are to be found in any given zone of its body. At last, the
whole mass forms a mere sac without any sign of organization, for
the brood at last completely destroys the body of the mother.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 573
Worm-fauna of Madeira.*—P. Langerhans has published the
fourth of his contributions on the worm-fauna of Madeira, in the
course of which he describes various new species and one new genus.
Among other points of interest the author has some suggestions as
to the divisions of the Serpulide, our knowledge of which is in a most
unsatisfactory condition. In that family he recognizes three types;
the first of these is Serpula itself, in which the thoracic segments
bear only one kind of dorsal seta; here belong Serpula, Hupomatus,
Pomatocerus, and Placostegus. Filograna is the second type, and in
it all the thoracic segments behind the second have, in addition to
the Serpulid sete, those of the kind first detected by Claparéde in
Salmacina. Here we have Spirorbis and others. The third type is
represented by Vermilia infundibulum, in which a fresh type of seta, ~
in addition to those already noted, is present.
Of the twenty species of Nemerteans found by Langerhans, seven-
teen are known to be members of the European seas.
New Species of Rotifer.t—Sara G. Foulke describes a new species
of rotifer under the name Apsilus bipera. In common with all
members of the genus, they possess, instead of rotatory organs, a
membranous cup or net, which is used for the capture of food. The
specific distinction of the new form consists chiefly in the structure
of the net, the presence of a true stomach in addition to the usual
crop, and the presence of cilia inside the net. It is proposed to unite
the forms Apsilus lentiformis Mecznichoff, Dictyophora vorax Leidy,
and Cupelopagus bucinedax, Forbes, and the new species in one genus,
Apsilus (Fam. Apsilide), in consequence of their strong points of
resemblance. These are, briefly, the presence of two eye-spots, of a
membranous cup, of a mastax exactly similar in all, of the absence
of tail or foot-stalk, of the absence of carapace, and of the similar
habits.
Prof. Leidy subsequently declared all four forms to form the same
species, with which opinion Miss Foulke does not agree.
Echinodermata.
Development of the Germinal Layers of Echinoderms.{—E.
Selenka finds that egg-cleavage in Echinoderms is regular, but that
of Ophiurids and Asterids is really “ pseudoregular,” and that of
Echinids regular with polar differentiation ; we cannot as yet exactly
define what we mean by a regular cleavage, and its various modifica-
tions are as yet insufficiently known; we may, however, distinguish
under its head those eggs into which the first two blastomeres are of
the same size, and those in which cleavage is on the whole regular,
with the exception of the first plane of cleavage. The various modes
of cleavage exhibited by the eggs of Echinoderms are of no value for
the phylogenetic history of the group; the influence of cenogeny is
* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 247-85 (3 pls.).
+ Proc. Acad. Nat. Sci. Philad., 1884, pp. 37-41 (1 pl.).
t ‘Studien iiber Entwickelungsgeschichte,’ ii., Wiesbaden, 1883, pp. 28-61
(6 pls.).
574 SUMMARY OF CURRENT RESEARCHES RELATING TO
apparent enough. The blastula is of the same thickness throughout ;
in Echinids, and probably also in Asterids and Ophiurids the blasto-
dermic cells are broader on the lower surface, in the Holothuroidea
they are of the same size all round. The mesoblast arises from the
primitive cells of the mesenchym and from the diverticula of the
archenteron. The former, by means of their daughter-cells, and in
the form of wandering cells, make their way into the blastoccelom and
give rise to the circular musculature of the fore-gut and to the cutis.
‘"he archenteric diverticula and their derivates consist first of a
single layer of cells, from which later on scattered cells arise peri-
pherally and form an outer ring of unicellular muscles. The
explanation of this double mode of origin is not easy; it may be
said that the two primitive cells of the mesenchym are the homologues
of the two primitive cells of the mesoblast of molluscs, Arthropods,
&ec., and that the archenteric diverticula are new formations (‘“ neo-
morphs”) ; while there are several good reasons to be given in support
of this hypothesis there are others that favour the view that the
diverticula form the primitive seat of origin of the mesoblast and
that the mesenchymatous cells are cenogenetic. Lastly, and this is
perhaps the best view of all, the mesenchym-cells are portions of the
archenteric diverticula, which in consequence of the modification of
the larval life, have precociously separated from the rest.
The “ blood-corpuscles ” of the water-vessels are found to arise from
epithelial cells of the rudiments of the water-vessels, and those of the
enterocelom from the peritoneal or ccelomic epithelium. -
Evidence of the vermian origin of Echinoderms is afforded by the
primary mesoderm having the form of two primitive cells, and by
the bilateral symmetry of the larval organs. The division of the
archenteric diverticulum into coelomic sac and water-vessels corre-
sponds physiologically to that which the mesodermic sac undone Qos in
Vertebrates, and to some extent in worms.
New Genus of Echinoids.*—Prof. F. Jeffrey Bell institutes a new
genus for the Hchinanthus twmidus described a few years since by
Mr. Tenison-Woods, on the ground that the rows of ambulacral pores,
instead of being approximated at their free end, tend to widen out in
a lyre-shaped fashion ; and the genus is thereby removed “ from the
direct line of ancestry through which the orthostichous passed to the
petalostichous Echinids.” He alludes to the significance of this form
being found in the Australian seas, and expresses a belief that further
research will result in the discovery of other forms which have been
unsuccessful in the struggle for existence.
Revision of the Genus Oreaster.{—Prof. F. Jeffrey Bell revises
the twenty-seven known species of Oreaster and describes five new
species; in the systematic disposal of the species he has attempted to
gain some assistance from the study of their post-larval development,
especially as regards the number and arrangement of their spines ; he
* Proc. Zool. Soc. Lond., 1884, pp. 40-4 (2 pls.).
+ Tom. cit., pp. 57-87.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 575
believes that “in the investigation of the spinulation of star-fishes
there is a wide field for the study of those mechanical causes with
which the zoologist is concerned.”
Organization of Adult Comatulide.*—F. Perrier finds in Antedon
rosaceus and A. phalangium that the “ axial organ ” is a tubular cavity
with glandular walls; of its diverticula some appear in section to be
cecal, while others are continued into canals, most of which pass
towards the dorsal integument and form around the cesophagus the
spongy organ of H. Carpenter. The canals (the author cannot call
them vessels) take a sinuous course, anastomose frequently, and have
walls which are clearly glandular; they open by ciliated infundibula.
The author regards all these as parts of one and -the same system,
and as comparable to the madreporic plate, sand-canal, and ovoid gland
of Echinids, Asterids, and Ophiurids. Perrier finds in the characters
of young larve—such as the disposition and mode of formation of the
single canal—facts which lead him to think that the organization of
the Comatulid is closely allied to that of other Echinoderms. Re-
serving details he here points out that if we consider an urchin as a
Crinoid whose arms have become firmly united with the disk (as is
the case, for example, in Eucalyptocrinus), and whose mouth was
situated at the point of insertion of the disk to the stalk, the nervous
system and the ambulacral canals of the urchin would have exactly
the same relations as those which are presented by the Comatulid.
He further remarks that the calyx of numerous Crinoids becomes
invaginated and presents points which are not without analogy to the
lantern of Aristotle in certain (and especially in Clypeastrid) Kehinids.
Ccelenterata.
Anatomy of Campanularide.j—It is generally believed that
the “theca” and the chitinous layer which covers the stem in the
Hydroida is a secretion from the ectoderm layer of the polyp. This
however docs not seem to be the case with the Campanularie.
H. Klaatch has been furnished by a detailed study of Clytia johnston
with evidence tending to show that the chitinous sheath of the
Campanularie is a product of differentiation of the ectoderm, an
epidermoid formation, the equivalent of a tissue. If this were not so,
and if the chitinous layer were a mere secretion from the ectoderm, as
it is in Cordylophora lacustris according to the researches of F. E.
Schultze, we should expect to find the whole of the body of the polyp
covered by a continuous layer of ectoderm entirely similar every-
where, and the growth of the chitinous covering to be increased by
the deposition of fresh layers of horny substance ; on the contrary, it
appears that the outer epithelium which covers the tentacles, the
head, and the “body” of the polyp is not continuous with that of
the stem, but at the posterior end of the stomach bends back and
becomes continuous with the calyx itself, actually passing into it, the
* Comptes Rendus, xeviii. (1884) pp. 1448-90.
+ Morph. Jahrb., ix. (1884) pp. 034-96 (3 pls.).
576 SUMMARY OF CURRENT RESEARCHES RELATING TO
process of the modification of the cells into horny matter having
been clearly recognized; ‘‘in the stem no outer epithelium can be
expected ; its absence is a proof that the chitinous sheath is a product
of the differentiation of the ectoderm.”
The chitinous theca therefore of Clytia is not homologous with
that of Cordylophora. Beneath this “epidermis layer” of Clytia
follows a deeper ectoderm layer, corresponding to the neuro-muscular
layer of Hydra, &c., which differs in the “ body ” and stem of the polyp ;
in the former there is a thick homogeneous layer to which the term
middle zone (“ mittelzone”) is applied; this in the stem and the disk
of the polyp becomes a distinctly cellular layer, one passing into the
other without any break; the outer cellular layer of the stem is not
therefore, as might appear from a casual inspection of Klaatch’s figure,
the equivalent of the outer ectoderm layer—the “ epidermis-schicht,”
but really represents the ‘“ mittelzone,” and has nothing to do with
the formation of the outer chitinous layer which is formed by a meta-
morphosis of the “ epidermis-schicht.”
The different conditions of the middle zone may be perhaps
explained by its different functions in the body and stem of the polyp
respectively ; in the body it undergoes alterations of diameter in
various stages of contraction, and from this fact appears to be rather
muscular than nervous in nature; in the stem, on the other hand, the
rigidity of the chitinous investment would seem to render the
presence of a muscular layer unnecessary, and it is very possible that
the cells which in this region of the polyp represent the “ muscular”
layer of the body are modified to form nervous structures which
receive impressions and control the movements of the muscular layer
of the body, with which, as has been already stated, they are in direct
connection.
Structure of the Velellide.*—M. Bedot finds that in young
Velellidz the two layers of which the crest of the pneumatocyst is
formed are not united together; they first appear as a fold of the
upper part of the pneumatocyst. The “liver” is of some complexity ;
on its upper or convex part there is a single layer of cells which is in
direct contact with the pneumatocyst; below this is a lamella, in
which no cellular structure could be made out; against this there are
applied the canals of the “ liver,’ which form a kind of roof fora
large mass of cnidoblasts; the presence of these last demonstrates
that the so-called liver does not perform hepatic functions. Below it
there are again some canals which differ from the more superior by
being unpigmented; they are attached to a similarly structureless
lamella. ‘The two sets of canals are connected with one another
through the substance of the organ.
The complicated vascular system arises simply as two straight
canals which open into the marginal one; they bifurcate at a short
distance from their point of insertion. In the course of their develop-
ment they become sinuous and give rise to a number of ramifying
czeca, which anastomose with those of the adjacent canals.
* Arch, Sci. Phys. et Nat., xi. (1884) pp. 328-30.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. wb
Actinie of the Bay of Naples.*—A. Andres publishes the first half
of his monograph, in which he limits himself to the bibliography and
systematic descriptions of the species; this is very fully done, and
the plates are of exquisite beauty.
Protozoa.
Morphology and Anatomy of Ciliated Infusoria.}—E. Maupas
commences an important essay with a brief review of the more
valuable works that have already appeared; after which he enters
on a description of Colpoda cucullus, the food of which is stated
to consist of bacteria, vibrios, micrococci, and small monads. Colpoda
steinit is next dealt with, in which four forms are distinguished.
These two species are very widely distributed.
A new genus Cryptochilum is instituted for the Cyclidiwm nigricans
of O. F. Miller, which, though closely allied to Paramecium, Col-
poda, Colpidium, and Cyclidium, may, the author thinks, be justly
distinguished from any one of them. A new species of this genus is
C. elegans, which is much larger than C. nigricans ; it was discovered
near Algiers. Paramecium griseolum of Perty is removed to this
genus; and C. tortum, found near Algiers, and C. echini, which was
found living parasitically in the intestine of Echinus lividus, are
described as new species.
Some parts of the structure of Colpidium colpoda are fully entered
upon; Glaucoma pyriformis (e) is described in detail, and the
structure of the mouth of G. scintillans is discussed. Ophryoglena
magna is anew Algerian species which is fully described and com-
pared with its allies.
A new genus Ancistrum is instituted for the Opalina mytili of
Quennerstedt, and for A. veneris galline, a new species found in
Venus gallina at Algiers. ‘They lead the life of commensals, and the
genus is allied to Pleuwronema and Ptychostomum. Quennerstedt failed
to notice the mouth, which is, however, really present.
Nassula oblonga (found in the sea off Roscott), Chilodon dubius which
might almost be made the type of a new genus, Holophrya oblonga
(sea off Algiers), and Lagynus crassicollis, from a similar locality, are
all new species. Lowxophyllum duplostriatum (new species) is remark-
able for the characters of its striation, which at once distinguishes it
from all its allies. Interspersed with and following these descriptions
are notes on some other species, after which the author enters upon a
discussion of the organology of the Oxytrichida. Before defining his
terminology he very justly urges that a good comparative morphology
can only be established by the aid of a very exact terminology, based
on as complete a comparison as possible. In the case of the Infusoria
this may seem to be impossible, but it is because it has not been
vigorously aimed at that such differences obtain in the comparative
studies of even the best naturalists. To cite some of the terms em-
* ‘Fauna und Flora des Golfes von Neapel. ix. Die Actinien,’ 1884, 459 pp.
(13 pls.).
t Arch, Zvol. Expér. et Gén., i. (1883) pp. 427-664 (6 pls.).
578 SUMMARY OF CURRENT RESEARCHES RELATING TO
ployed: the ventral surface always carries the mouth and the various
appendages which function in locomotion and in the production of the
nutrient currents ; the prebuccal and postbuccal regions vary greatly
in their proportional extent, and it would seem that the suppleness
and contractility of the body stand in an inverse relation to the
development of the prebuccal region; this may be distinguished into
a peristome and a lateral area; and they, also, differ in the pro-
portional extent to which they are developed. Four kinds. of
appendages may be distinguished: vibratile cilia; cirri, which are
stylet-shaped, and much larger at their base than at their free-end,
and which may be abdominal, transverse, or marginal; sete, which
are filiform, homogeneous, and simple, but rigid like needles, and
which may be dorsal or caudal; the latter are much longer and
stronger ; lastly, the vibratile membranes are either those properly so
called, or are buccal “ membranelles.”
Actinotrocha saltans, Gonostomum pediculiforme, Holosticha lacazei
n. sp. (seas near Algiers), H. multinucleata n. sp. (port of Algiers),
Uroleptus roscovianus n. sp. are then described.
The author proposes to replace the terms Protozoa and Metazoa
by those of Cytozoa and Histozoa.
Attention is directed to the characters of the naked Infusoria,
which are not all members of the group Acinetz, but are found also
among the Ciliata. The existence of forms without an integumentary
layer shows that its presence or absence is in no way associated with
the grade of development to which a Cytozoon may arrive, but that the
protoplasm is ready to take on the most varied forms and structure,
without the addition of an external protecting layer. The views of
Hackel as to the typical constitution of the integument of an
Infusorian are discussed, and the conclusion is come to that the
‘cuticular layer” is perfectly distinct from the skeletal cuticular
formation, that the ciliary and myophanous layers have no existence,
and that the layer of trichocysts is a part of the sarcode and not of
the integument. Contrary to the views of Hackel, with regard to
whom Maupas expresses himself in the most energetic manner, the
integument of ciliated Infusoria is looked upon as corresponding
morphologically to the membrane of the cell, of which it has all the
physical properties. The integument is, in fact, defined as any distinct
superficial layer, which is intimately applied to the surface of the
cell, and lives the same life as it does. The various conditions under
which it presents itself are then described.
The physiological properties of the sarcode or cytosome strike one
by their resemblance to those of the body of the Rhizopoda, and lead
one to think that an Infusorian may be defined very exactly as a
Rhizopod inclosed in an integument and provided with appendages
which are destined to fulfil the external functions which the sarcode
of the Rhizopod performs for itself.
The author’s observations on the trichocysts are stated by him to
confirm those of Allman. The doubly refractive bodies which have
been ordinarily regarded by those who have studied them as urinary
concretions, offer us an important specific character, as they may be
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 579
present in one species and absent from another which closely
resembles it. The fibrillated appearance of some of the appendages is
regarded as being due to the coalescence of separate cilia. When the
integument is highly differentiated and very distinct from the
underlying sarcode, the orifice of the contractile vacuole is re-
presented by a permanent and constantly visible pore. The author
concludes with some observations on the nucleus and nucleolus, in
which he insists on the fact that the latter is certainly absent from
some forms, even in those that are multinucleated, and he points out
the difficulty which this absence presents to our accepting the views of
Balbiani as to the mode of conjugation of the Ciliata.
Trichomonas vaginalis.* —J. Kiinstler has now published the
full text of his article on this flagellate, a preliminary notice of which
was given ante, p. 67.
Acanthometra hemicompressa.{—Dr. L. Car gives an account of
this new Radiolarian which is characterized as follows :—The
spicules are long and thin, pointed at the extremity ; the basal portion
is quadrangular, the distal half is circular in transverse section, the
proximal half lenticular, the two halves are of equal breadth, and
this distinguishes the species from <A. compressa ; the spicules are
elastic, but the elasticity is not so well marked as in A. elastica; the
basal portion which is inserted into the central capsule is quadrangular
and provided with triangular wing-like processes ; it terminates in a
fine point; although these spicules are so elastic they appeared
usually to be broken. The central capsule is transparent, and the
distal portion only of the spicules projects outside; as in other
Radiolarians the central capsule contains a number of colourless
and yellow cells. In its general characters this species is inter-
mediate between A. elastica and A. compressa.
Orbulina universa.{—The life-history of this foraminifer has
been a subject of much discussion. Pourtalés and Krohn both observed
what was apparently a Globigerina in the interior of many Orbuline,
and came to the conclusion that Orbulina was merely a stage in the
life-history of Globigerina ; this opinion was combated by Carpenter,
who adduced numerous reasons for retaining the two genera Orbulina
and Globigerina as defined originally by D’Orbigny.
C. Schlumberger, in numerous specimens of Orbulina universa
dredged during the voyage of the ‘ Talisman’ from a depth of about
2000 fathoms, observed the same phenomenon ; of the smaller examples
some contained within their cavity a “succession of globular
chambers, arranged in a spiral fashion, like those of certain Globi-
gerine,” while others did not contain any trace of such a structure ;
the very large specimens also were nearly always empty.
On examining with care this Globigerina-like body its “ plasmos-
tracum ” was found to be extremely fine, and traversed by widely
scattered perforations ; the chambers forming the two first turns of
* Journ. de Microgr., viii. (1884) pp. 317-31 (2 pls.).
¢ Zoo). Anzeig., vil. (1884) pp. 94-5.
} Comptes Rendus, xeviii. (1884) pp. 1002-42,
580 SUMMARY OF CURRENT RESEARCHES RELATING TO
the spiral are quite smooth, whereas the following ones are provided
with spines which reach as far as the outer wall of the Orbulina and
are there fixed firmly to it; the several chambers communicate with
each other and also with the interior of the Orbulina.
Now in an independent Globigerina the plasmostracum is always
relatively thick, the perforations are close together, in short, it differs
in many respects from this Globigerina-like body with which it only
agrees in a general similarity of form.
It appears, therefore, that the most probable explanation is that
Orbulina is another instance of dimorphism among the Foraminifera
such as has already been shown to exist in other genera of that order
by the author and M. Munier-Chalmas.
Nuclear Division in Actinospherium eichhornii.*—A. Gruber
has a note on R. Hertwig’s observations on the division of the nucleus
of this Protozoon. In the resting nucleus Hertwig distinguishes a
nuclear membrane, which is best seen after the addition of reagents,
the nuclear substance, and the framework of achromatic substance
therein suspended. In the nucleolus there may be distinguished from
the nuclein (chromatin) paranuclein which does not take up colouring
matter and is much smaller in quantity ; the nucleolus varies greatly
in form, and may become completely broken up into two or more
nucleoli; there are often as many as six or even twenty, and they
then form fine rods united into a rosette.
When the nuclei begin to divide there appear two special proto-
plasmic cones, which lie outside the nucleus, and which, though they
give rise to a spindle-shaped body, are clearly not the so-called
nuclear spindles. The nucleolus next begins to break up, and the
nucleus forms a sphere filled with regularly distributed and very fine
granules ; these pass to the periphery, where they give rise to two
hyaline caps and an equatorial band of granules. In this last there
appears a dark band, the nuclear plate, and in the rest of the granular
mass fine filaments which give rise to the polar plates. These fila-
ments traverse the nuclear plate and so form a system which extends
directly from pole to pole. Lateral plates become formed which have
the concave side directed towards the centre of the mass, and from
these arise daughter-nuclei which form small, rounded, finely granular
bodies.
It is clear from these observations that the nuclein in the nucleus
of Actinospherium is not a spongy framework ; the processes described
are intermediate between the phenomena which obtain in other
Protozoa on the one hand, and in animal and vegetable cells on the
other. As in the former, the nucleus is sharply limited at every stage
of division, and undergoes a biscuit-like constriction; the internal
changes remind one rather of what obtains in wulticellular organisms.
The remarkable polar plates find their homologues in the nuclei of
the infusorian Spirochona gemmipara. Gruber ascribes the errors in
his own previously published observations to the imperfect preserva-
tion of the material with which he had to work.
* Biol. Centralbl., iv. (1884) pp. 233-6.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 581
BOTANY.
A. GENERAL, including Embryology and Histology of the
Phanerogamia.
Homology of the Reproductive Organs in Phanerogams and
Vascular Cryptogams.*—L. Celakovsky has made a fresh detailed
investigation of this subject. He maintains his previous view, held
also by Warming and Prantl, of the homology of the integuments of
the ovule with the indusium of ferns, as is sufficiently proved by the
phenomena of phyllody of the ovule, which show. that the ovule is
due to a transformation of a segment of a fertile leaf together with
the nucellus or macrosporangium belonging to it; the integuments
being formed from it in just the same way as the indusium from the
fertile leaf-tip of the Filicine. The nucellus is formed directly from
the upper part of the ovular papilla; the integument then springing
from its base and enveloping it; this being followed in most cases b
a second envelope formed in the same way outside the first. The
nucellus being homologous to a sporangium, the mode of formation
of the ovule coincides with that of the sporiferous leaf-segment of
Lygodium, the sporangium of Lygodiwm being formed at the apex of
a segment of a fertile leaf, just like the nucellus on the ovular papilla,
and the indusium round the sporangium just like the single or
double integument round the nucellus. In Trichomanes the only
difference is that the sporangium is replaced by the sporiferous
receptacle. When normally dichlamydeous ovules undergo phyllody,
they become monochlamydeous, and form a simple stalked cup which
corresponds to the integuments, the stalk corresponding to the
funiculus. The nucellus sometimes occupies its normal terminal
position at the bottom of the cup, sometimes it is pushed towards its
rim. The segment of a fern-leaf which bears the indusium on its
under side corresponds to the outer ovular integument in Angio-
sperms.
In the Hymenophyllacez the indusium is not formed from the
apex of the leaflet which corresponds to the nucellus or receptacle of
the sorus, but as a lateral new formation, The single terminal
sporangium appears to be more archaic than the polyangic sorus with
its receptacle. The author believes that the sexually produced
generation (non-sexual generation) of the first Vascular Cryptogams
originated from the branching of the sporogonium of a moss. The
sporangium of ferns is then homologous, from a phylogenetic point
of view, to the sporangium of mosses, notwithstanding its different
morphological value. The sporangium of Schizeacew is an older
stage of development, and that of Ophioglossacez older still, where the
integuments are entirely wanting, and the sporangium is therefore
formed from the greater part of the leaflet, perfectly homologous to
the naked ovule of the Santalacese, Balanophores, and Crinwm.
* Pringsheim’s Jahrb. f. Wiss. Bot., xiv. (1884) pp. 291-378 (3 pls.).
582 SUMMARY OF CURRENT RESEARCHES RELATING TO
The original position of the nucellus on the leaf-segment is always
terminal ; but as soon as the leaf-segment assumes a foliar character,
it takes its place on its upper side; and this is a universal law for
vascular cryptogams and phanerogams alike.
If we now look at the homologies of the reproductive organs out-
side the true Filices, we see that the fertile leaves of cryptogams with
marginal sporocysts, like Botrychium and Ophioglossum, are the proto-
type of the carpids of Phanerogams with marginal ovules; and that
the fertile leaf of Lycopodiwm with axillary or subaxillary sporocyst,
is the prototype of a carpid with axillary ovule, like Huphorbia and
Ranunculus ; and that this is also the case with a carpid with ovule
terminal to the axis of the flower, like Polygonum, which, notwith-
standing this position, undoubtedly belongs to a carpid of the
ovary.
With regard to the phenomena of coalescence in the various
groups, Celakovsky makes the following observations :—
1. In Angiosperms the trumpet-shaped carpellary leaves of a flower
coalesce into a septated ovary. 2. In Marsileacez the cornet-shaped
leaf-segments of a fertile leaf coalesce into a 2- or multilocular sporo-
carp, the homologue of an integumented ovule. 3. In Psilotee the
sporangia coalesce with one another as the homologue of a branched
but naked ovule. In Marattiacee the numerous emergence-like
sporangia coalesce into a multilocular homologue of coalescent nucelli
of an ovule.
As regards the ovules of Gymnosperms, those of Cycadex are
distinguished from the homologous sporangia of the Ophioglossacez
only by being invested with an integument; and their carpellary
leaves from the fertile leaves of Ophioglossaceze only by the latter
being bifurcate.
The Conifere are divided by Strasburger into two main groups:
(1) the Araucariacee (including the Araucariew, Abietinez, Cupres-
sinew, and Taxodiee), and (2) the Taxacee (including the Taxes,
Podocarpew, and Cephalotaxez), which differ so greatly in their
morphological characters that they must be considered separately.
The ovules of the Araucariacez have only a single integument,
and spring from the under side of the carpids which coalesce into a
fertile scale and stand in the axil of a bract; turning towards it,
according to the law of inversion, their upper side, and coalescing with
it slightly in the Abietinez, very closely in the other families. The
phenomena of prolification of the cone show that in the Abietines
the simple scale-like carpels produce each one ovule on its under side.
This is a carpel in its simplest possible form, and homologous to the
possible case in which the fertile leaf of a cryptogam, e. g. Lycopo-
diacez, should produce a single indusium on its under side. This is
also the most probable interpretation of the structure in the Cupres-
sinew and Taxodiee, though not so certainly as in the Abietinee.
In Taxaceze the ovule has two integuments, except in Gingko
(Salisburia) and Cephalotaxus, and is inserted on the upper side of the
carpel, sometimes higher, sometimes at the base or in the axil of the
leaf. The “cones” of the Cycadex, Podocarper, &c¢., are flowers
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 583
composed of carpels, while those of the Araucariaces are true spikes,
the bracts of which produce the coalescent carpels in their axils.
The mode of formation of the anthers differs in Gymnosperms
and Angiosperms. The type of stamen in the Coniferze and Gnetaces
is derived from that in the Equisetacem, and more remotely from that
in the Ophioglossacew ; the stamens of Cycadex corresponding to the
more or less peltate type in ferns with sori on the under side,
especially in Gleicheniaceew and Marattiacee.
The anther of Angiosperms is developed from a sporophyll of the
Ophioglossacee, but in a different way from that of Conifers, viz.
from the form in Ophioglossum rather than in Botrychium or Helmin-
thostachys. The difference between a pollen-sac of Conifers and a
loculus of the anther of Angiosperms, is that the former is homo-
logous to a single sporangium, the latter to a row of coalescent
marginal sporangia. The normal anther of Angiosperms is also dis-
tinguished by the peculiarity of having not two but four loculi, as is
clearly shown by the phenomena of phyllody of the stamen.
Influence of Light and Heat on the Germination of Seeds.*—A
fresh series of experiments on this subject, undertaken by A. Cieslar,
leads him to the conclusion that the effect of light on the germination
of seeds is very complicated, and varies with the species, depending
greatly on the amount of reserve food-material in the seed. The rays
of different refrangibility also produce different effects. In white
and yellow light much greater development takes place than in violet
light or in the dark; and this difference increases with increase of
temperature. He believes the effect to be greatly due to a trans-
formation of light into heat. The production of substances which
cause osmose in seedlings growing in white or yellow light is favour-
able to germination, by bringing about increased root-pressure.
Seeds with but a small amount of reserve food-material germinate
better in light than in darkness; light promoting not only the
peuetration of the roots into the soil, but also the copious production
of roots.
A. Ritter von Liebenberg{ confirms these conclusions on the
whole, and regards the intermittent heat resulting from alternation of
day and night as distinctly favourable to the germination of seeds.
Origin of the Placentas in the Alsinew (Caryophyllez).{—Miss
G. Lister, in view of the fact that in Lychnis the first developed ovules
are developed along the unattached margins of the dissepiments in
the upper unilocular portion of the capsule, the placentas being
therefore carpellary, considers that as the capsule in Alsine is
developed on essentially the same plan as that of Lychnis, we are
bound to admit that the placentas in the Alsinex, from Sagina apetala,
which most resembles Lychnis, to Cerastiwm triviale which most widely
differs from it, are carpellary also.
* Wollny’s Unters. aus d, Geb. der Agricultur-pbhysik, vi. (1883). See Bot.
Centralbl., xviii. (1884) p. 15.
+ Bot. Centralbl., xviii. (1884) pp. 21-6.
t Journ. Linn. Soe, Lond.—Bot., xx. (1884) pp. 423-9 (4 pls.).
.
584 SUMMARY OF CURRENT RESEARCHES RELATING TO
Gemmez of Aulacomnion palustre.*—This moss was found in
1882 growing in the propagating pits at Kew, where it flourished
without, however, showing any trace of sexual organs. F. O.
Bower finds that ordinary vegetative axes often bear towards their
apices structures of a foliar nature, and show a special adaptation
for effecting the asexual or vegetative reproduction of the plant. On
passing upwards along one of these axes or pseudopodia, there is
found a gradual transition from the normal leaf to the leaf-gemme,
which are readily removed from the plant by a slight mechanical dis-
turbance, and are then capable of immediate germination when laid
on damp soil or floating in water.
Relation between Increase and Segmentation of Cells.;—Prof.
Beketoff criticizes Sachs’ theory as to the relations between the
increase and segmentation of cells in the embryonal parts of plants.
While he warns one against the application of geometrical theories to
botany, he points out how some of the conclusions arrived at by
Sachs could be more easily explained by the principles established by
Hofmeister.
Development of Starch-grains in the Laticiferous Cells of the
Euphorbiacez.{—The development of the starch-grains in the latici-
ferous cells of the Euphorbiacez is described by M. C. Potter as
taking place in the interior of rod- or spindle-shaped starch-forming
corpuscles which lie in the parietal protoplasm of the cell.
The starch-grain is at first visible, through the agency of iodine, as
a thin streak in the interior of the starch-forming corpuscle. This
streak, through the deposition of starch, assumes a rod- or spindle-
shape ; it increases in length and breadth, the starch-forming corpuscle
at the same time increasing. When the starch-grain has attained nearly
to its maximum dimensions in length and breadth, the starch-forming
corpuscle collects at both ends of the rod-shaped grains, and there
forms the masses of starch at the end of the rod, causing it to assume its
remarkable shape, resembling a bone. The starch-grains are doubly
refractive, but instead of the black or white cross of other starch-
grains they show a central black (or white) line surrounded on both
sides by white (or black) lines.
Constitution of Chlorophyll.s— E. Schunck extracts leaves with
boiling alcohol, and after some time filters ; the filtrate is mixed with
its own volume of ether and two volumes of water; it then forms two
layers, which are separated. The lower layer is yellow, and reduces
Fehling’s solution. The upper layer is green, and contains all the
chlorophyll; it is thoroughly washed free from everything soluble in
water. When the ether is evaporated the bright green residue,
dissolved in alcohol and treated with alcoholic potash, does not reduce
Fehling’s solution, but if it is previously treated with concentrated
* Journ. Linn. Soc. Lond.—Bot., xx. (1884) pp. 465-7 (4 figs.).
+ Mém. Soc. Naturalistes St. Pétersbourg, xiii. See ‘ Nature,’ xxix. (1884)
p. 461.
{ Journ. Linn. Soc. Lond.—Bot., xx. (1884) pp. 446-50 (4 fies.),
§ Proc. Roy. Soc., xxxvi. (1884) pp. 183-5, 285-6.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 585
sulphuric acid in the cold, or if its alcoholic solution is boiled with
hydrochloric or sulphuric acid, the alcohol driven off, the residue
treated with water, filtered, and the filtrate made alkaline, mixed with
Fehling’s solution and boiled, the usual glucose reaction is obtained.
The glucose or glucose-like substance is a pale-yellow gummy
compound. The author, therefore, concludes that chlorophyll is either
a glucoside, or is associated with a glucoside.
Cellulose accompanying the Formation of Crystals.*—A. Poli
has already noted f the occurrence in the pith of a number of plants
belonging to the order Malvacezx, of clusters of crystals attached to
the cell-wall by strings of cellulose. He has now examined more
closely the structure of these strings, and finds them to be hollow
tubes. They generally exhibit swellings here and there, and bright
refringent spots, which are probably the points of origin of new
crystals. Their composition is the same as that of the cell-wall, and
they not unfrequently become lignified in the same way. They
appear to occur in all the arborescent species of the order, most beau-
tifully in Malvaviscus mollis, but have not been observed in Malva
sylvestris.
Middle Lamella of the Cell-wall.{—In the course of his investi-
gations on the continuity of protoplasm through the walls of cells,
W. Gardiner has investigated the structure of the middle lamella of
cell-walls, formerly known as “ intercellular substance.” He found
the mucilaginous degeneration of the cell-wall to be a phenomenon
of very frequent occurrence; and that this mucilage is very liable to
be mistaken for protoplasm, owing to its being also stained by
Hofmann’s blue. In certain cells, such as bast-prosenchyma cells of
the pulvini of Mimosa, and the endosperm of many palms, the cell-
walls consist of pure cellulose, and the middle lamella is but little deve-
loped ; it is more resistant, but still distinctly soluble in sulphuric
acid. In other instances, such as the lignified prosenchyma cells
of the cortex of Lycopodium, it is well defined, but lignified, like the
rest of the layers. In other cases it may be at once converted into
mucilage. The great point with regard to middle lamellas other
than cellulose is that in their substance the maximum amount of
change appears to have taken place, i.e. almost the whole of the
cellulose has been converted into lignin, cutin, or mucilage, as the
case may be, and thus but little of the cellulose framework left,
This will explain the fact that, after treatment with Schulze’s mixture
or other oxidizing agent, the various cells readily separate from one
another ; for the whole of the middle lamella has dissolved, the cellu-
lose framework of the cells alone remaining. It would thus appear
that in unaltered cellulose walls the middle lamella consists of dense
cellulose, while in lignified, cuticularized, corky, or mucilaginous
cells the changes which occur in the middle lamella are of the same
character as those of the rest of the membrane, and have reached
their maximum.
* Nuoy. Giorn. Bot. Ital., xvi. (1884) pp. 54-6 (1 pl.).
+ See this Journal, ii. (1882) p. 597.
t Proc. Camb, Phil, Soe., v. (1884) pp. 1-20,
Ser, 2.—Vou. IV. ZR
586 SUMMARY OF CURRENT RESEARCHES RELATING TO
Intercellular Spaces between the Epidermal Cells of Petals.*
—While the cells of the epidermis of leaves fit close to one another
without any intervening spaces except the stomata, the case appears
to be very different, according to G. H. Hiller, with the epidermis of
petals, where there are very often spaces between the cells, especially
in Dicotyledons. The size and form of these spaces vary with the
species; in Linum usitatissimum they have a breadth of from 2°63 to
7°175 p, and a length of from 13°15 to 15°78 yw. The largest
measured had a diameter of 18. They are situated either between
the walls of the cells themselves, and then usually at the point of
contact of several cells, or in rib-like foldings of the cell-walls. On
the inner side of the leaf they are usually open, where not acci-
dentally covered by a parenchyma-cell, while on the outer side they
are always covered by the cuticle. They almost always originate
from ribs which must be regarded as foldings of the cell-wall, which
ribs split at a certain stage of development. Very rarely they occur
in epidermis with straight-walled cells, and then always from their
effort to round themselves off. They are then always found at the
point of contact of several cells. Intercellular spaces of this kind
may be observed in the petals of Musa rosacea and Hrythrina crista-
galli.
Contents of Sieve-tubes.;—E. Zacharias has examined, by ordi-
nary macrochemical tests, the contents of the sieve-tubes of Cucurbita
Pepo, which flow out in large quantities when the stem is wounded,
and can be readily separated from the cell-sap. They consist of
albuminoids, non-albuminous organic substances, and inorganic salts.
The albuminoid substances readily separate from the juice which
flows from the sieve-tubes, after standing for a short time, in the form
of a transparent, colourless, moderately stiff jelly. Chemical tests
show that this substance is of the nature of fibrine, mixed with a small
quantity of a substance insoluble in the gastric juice and in dilute
potash ley. When this substance has been removed by concentrated
alcohol, the filtrate turns the plane of polarization to the right. The
substance which remains is of the nature of dextrin, which is trans-
formed into glucose by dilute sulphuric acid. The presence of a
nitrate or nitrite can also be determined both in the aqueous solution
of the substance and in its ash. The question of the presence or
absence of amido-acids and of organic nitrogenous compounds soluble
in water in the contents of the sieve-tubes was not satisfactorily
settled.
Of inorganic salts there was found in the ash distinct evidence of
the presence of magnesia. The probable presence in the sieve-tubes
of potassium phosphate was also indicated, and to this is probably due
the alkaline reaction of the juice.
Organs of Secretion in the Hypericaceze.{—J. R. Green describes
the organs that secrete the ethereal oil or resin with which the
* Ber. Deutsch. Bot. Gesell., ii. (1884) pp. 21-3.
+ Bot. Ztg., xlii. (1884) pp. 65-73.
{ Journ. Linn. Soc. Lond.—Bot., xx. (1884) pp. 451-64 (2 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 587
tissues of the Hypericacere abound. He concludes, (1) that the view
advocated by Link, Martinet, and de Bary of the lysigenous origin
of the reservoirs of ethereal oil in these plants is the correct one.
(2) That there exists in many parts of the plants a series of ducts
or passages differing only slightly from these reservoirs ; the differences
being that they are not globular and isolated, but are generally
connected more or less intimately with each other, and that their
secretion is not a clear ethereal oil, but a viscid or resinous liquid, the
points of agreement being those connected with their development and
function. (3) In some species at least there is also a series of
schizogenous ducts confined to certain portions of the phloém. (4)
There are certain dark glands described in the paper which are in
intimate relationship with the fibrovascular system. (5) The formation
of resin and kindred secretions in these plants is confined to the parts
where metabolism is active, and where there is a primary meristem.
All such parts give evidence of such formation with the exception of
the roots.
Tracheids of Gymnosperms.*—M. Scheit describes the group of
peculiarly thickened cells (the tracheid-seam of dé Bary) found in the
leaves of conifers on both sides of the vascular bundle, at one time
considered as a part of the transfusion tissue. In the living condi-
tion these are filled with water or aqueous vapour, but not with air,
as is shown by placing twigs of Pinus Pumilio in turpentine oil.
The cells themselves are true tracheids, exhibiting sometimes a reti-
culate thickening, sometimes bordered pits. These “seams” occur
not only in conifers, but also in the other orders of Gymnosperms,
the Gnetacez and Cycadex, where they consist of very small and few
cells, greatly resembling the adjoining parenchymatous cells in the
mode of thickening. They are therefore an anatomical characteristic
of Gymnosperms generally.
The variation in the mode of thickening in these cells corresponds
to their function as a protection against the pressure of neighbour-
ing turgid cells. Where the “seams” are separated from the
parenchyma of the leaf by thickened sheaths, the tracheids have only
bordered pits; when they are in immediate contact with the paren-
chyma, they are thickened reticulately. The extent of development
of these “seams” depends on the intensity of transpiration of the
species. In Pinus Pinea, which spreads its crown as wide as pos-
sible beneath the clear sky of Italy, they are very strongly developed ;
while in Pinus Strobus, which prefers moist climates and thrives best
in bogs, they are but very feebly developed.
Apparatus in Leaves for Reflecting Light.t—O. Penzig has ex-
amined the structure of the clusters of crystals found in the leaves of
the Aurantiaces, clothed with cellulose, and attached to the wall of
the mother-cell—the idioblasts of Pfitzer; and believes they are
* Jenaische Zeitschr. f. Naturwiss., ix. (1883) (1 pl.). See Bot. Ztg., xlii.
(1884) p. 74.
+ Atti Soc. Nat. di Modena, i. (1883) (1 pl.). See But, Centralbl., xvii. (1884)
p. 333. ,
2R2
588 SUMMARY OF CURRENT RESEARCHES RELATING TO
connected with the dispersion of the rays of light in the dense pali-
sade-tissue. They always have their principal axis vertical to the
surface of the leaf, and are fixed in this position by a peculiar band of
cellulose. The rays of light fall, therefore, parallel to the principal
axis of the crystals, and are dispersed on all sides from their reflect-
ing surfaces, while those which pass through the crystals are refracted
obliquely. It is possible that the subepidermal cystoliths in the
leaves of Ficus have a similar property.
Swellings in the Roots of Papilionacex.*—F. Schindler has
reinvestigated this subject, with reference to the previous researches
of other observers; and has come to the conclusion that the peculiar
swellings are not due to the attacks of a parasitic fungus, but to
hypertrophy of the tissue surrounding the vascular bundles, though
in some cases there appears to be a phenomenon akin to symbiosis.
The species in which the peculiar structures were observed, were
Trifolium pratense, Vicia villosa, Phaseolus vulgaris, and Lupinus.
Origin of Adventitious Roots in Dicotyledons.t—A. Lemaire
discusses Van Tieghem’s statement that lateral roots have their origin
in the peripheral layer of the central cylinder which he denominates
the pericycle, and points out that all Van Tieghem’s examples are
drawn from Monocotyledons. Lemaire finds among Dicotyledons two
types, the first in which they spring from interfascicular spaces, the
second from the pericycle, or layer of the central cylinder immediately
beneath the endoderm. Im the latter case they are always produced
in the neighbourhood of large primary bundles. The cellular portion
of the pericycle of two plants examined (Mentha arvensis and Veronica
Beccabunga) divides by tangential walls into two layers, the inner of
which produces the central cylinder, the outer one again dividing into
two layers. The lower of these gives rise to the cortex, while the
peripheral layer developés, by successive divisions, into the cap and
piliferous layer of the root.
Crystals of Silex in the Vascular Bundles.{ — Pursuing the
researches of G. Licopoli, R. F. Solla has examined the clusters of
siliceous crystals found in the fibrovascular bundles of a number of
species of palm, especially Chameerops humilis and Phenix dactylifera.
He finds them in rows in the immature fruit of the first-named and
in the trunk of the last-named species, in the latter case occurring
also in the vascular sheath. They are found also in the scleren-
chymatous cells in the endosperm of the seeds of Chamerops humilis,
and in the spathe of Cocos Yatai. 'They vary greatly in size according to
the species ; their chemical reactions show them to consist of pure silica.
Effect of Heat on the Growth of Plants.s—Following out his
researches on this subject, J. Wortmann gives the minimum, the
optimum, and the maximum temperature for growth in various plants.
As a general law, it may be stated that thermotropism is a phe-
* Bot. Centralbl., xviii. (1884) pp. 84-9. Cf. this Journal, iii. (1880) p. 115.
+ Bull. Soc. Bot. France, xxx. (1884) pp: 283-5.
{ Nuov. Giorn. Bot. Ital., xvi. (1884) pp. 50-1.
§ Biol. Centralbl., iv. (1884) pp. 65-71. Cf. this Journal, iii. (1883) p. 873.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 589
nomenon of irritation altogether analogous to heliotropism, and that
hence, in order to bring about thermotropic curvatures, the only factor
to be regarded is the direction in which the rays of heat, if of sufficient
intensity, strike the part of the plant in question.
Curvature of Roots.*—J. Wiesner has made a further investiga-
tion of the “darwinian” and the geotropic curvature of roots, with the
following results :—
1. The so-called “darwinian” curvature of roots, caused by injury
to one side of the apex, has a double character, a secondary curvature
taking place above the maximum zone of growth, while the primary
curvature is below it.
2. The primary curvature is the result of growth, the secondary
curvature simply of turgidity, the cells above the injured spot in-
creasing in length. If the root is decapitated, the zone above the
wound, within which the darwinian curvature takes place, is elongated,
the cell-walls becoming more extensible.
8. The darwinian curvature combines with other paratonic
nutations, as for example with geotropic curvature. Geotropism
frequently neutralizes the darwinian curvature.
4. The entire growth of decapitated roots grown in damp media
is less than that of those that remain uninjured; while the lower zone
of such roots nearest the apex undergoes great extension in consequence
of the increase of extensibility of the cell-walls. In decapitated roots
grown under water this pathological increase in length is so great
that the total growth of such roots is greater than of unmutilated ones.
5. The decapitation of roots causes a diminution of the turgidity
of the cells; and since geotropic curvature decreases with this
diminution, it follows that decapitated are less geotropic than uninjured
roots. ;
Torsion as a Cause of the Diurnal Position of Foliar Organs.;—
According to O. Schmidt, light, by promoting the growth in length of
the shaded side of organs, can produce curvatures, but not torsions.
So-called heliotropic torsions are due to the action of gravitation.
The ordinary diurnal position of leaves is a result of the combined
action of light and of gravity, the latter causing the torsion without
which the position could not be attained.
Assimilative Power of Leaves.t—J. Sachs has carried out a series
of experiments on a number of plants growing in the open ground,
for the purpose of ascertaining the phenomena connected with the
formation of starch in the chlorophyll-grains, and its disappearance
under normal conditions of vegetation. The results arrived at are
very remarkable, in showing the extraordinary rapidity with which
starch is formed and again disappears when the conditions of vegeta-
tion are favourable. The plan pursued was to remove the chlorophyll
by alcohol, and then employ the iodine test to determine the presence
of starch. Leaves may be perfectly decolorized by first boiling in
* Anzeig. K. Akad, Wiss. Wien, 1884. See Bot. Centralbl., xviii, (1884) p. 95.
+ Ber. Deutsch. Bot. Gesell., i. (1883) pp. 504-11.
t Arbeit. Bot. Inst. Wiirzburg, iii, (1884) pp. 1-33.
590 SUMMARY OF CURRENT RESEARCHES RELATING TO
water for a few minutes, and then for a short time in alcohol. If
then placed in a strong alcoholic solution of iodine, the decolorized
leaf will be stained a buff-yellow if no starch is present, blue-black if
starch is present in great quantities, with intermediate shades according
to the amount of starch.
The formation of starch is entirely dependent on the presence of
light; and Sachs’s experiments show that the starch formed during
the day may disappear completely during the night; the cells of the
leaves being full of starch in the evening and quite empty in the
morning, when the conditions of temperature are favourable. It is
stated that the starch disappears in the form of soluble glucoses,
which travel, through the vascular bundles, to the parts where they
are wanted for purposes of growth. Although this process takes place
chiefly in the night, it is also going on more slowly through the day,
but is then masked by the much more energetic production of starch.
The transformation of starch into sugar may possibly be due to the
presence of a diastatic ferment in the cells of the leaf.
By an ingenious contrivance the quantity of starch produced and
converted into glucose was approximately measured. In Helianthus
annuus 4°64 grms. disappeared in ten hours from 1 sq. m. of leaf-
surface; and in the same plant 9:14 erms. were formed in the same
time on the same area. In another case, where the leaves were
removed from the stem to prevent the return of the starch from the
leaf to the stem, a sq. m. was found to produce starch at the rate of
1-648 grm. per hour. As a general result, Sachs concludes that, in
ordinary circumstances, a leaf may produce in the day from 20 to 25
erms. of starch per sq. m. of surface; and under certain conditions
it may even be larger.
Quantitative Relation between Absorption of Light and Assimi-
lation.*—T’. W. Engelmann gives the result of a number of observa-
tions on this point, accompanied by mathematical formule. He
regards the bacteria-method | as far the most exact for the purpose.
The general results may be stated as follows :—The absolute minimum
of absorption lies in the outermost red. Between B and BE, to the
highest degree at F, lie one or more maxima and minima. The
amount of absorption increases constantly, attaining its maximum in
the more refrangible part of the visible spectrum. The amount of
assimilation corresponds to the amount of absorption in all cases from
the outermost red to the green; while in the more refrangible part
the amount of assimilation falls notwithstanding a regular increase
of-absorption.
Causes which Modify the Direct Action of Light on Leaves.t—
Pursuing this subject, E. Mer arrives at the following conclusions :—
1. The position of leaves is not always an index of their direct
relation to light; for this sometimes results from influences which
modify more or less the direct action of light.
* Bot. Ztg., xlii. (1884) pp. 81-93, 97-105 (1 pl.).
+ See this Journal, iii. (1883) p. 390.
us ppomples Rendus, xeviii. (1884) pp. 836-8. Cf. this Journal, iii. (1883)
p. vd0.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 591
2. The diurnal sleep of leaves must not always be regarded as a
result of this action acquired to protect them from too great radiation ;
for if, in certain cases, either their position or the direction of the
rays of light is changed, they do not again place themselves in a
position to be illuminated by the most oblique incidence.
3. The terms diaheliotropism and paraheliotropism, employed in
their wide signification, must therefore serve only to indicate the
positions of leaves in reference to the direction of the rays of
light, without expressing an opinion on the causes which produce
them.
Respiration of Leaves in Darkness.*—G. Bonnier and L. Mangin
find that, in the case of green leaves growing in darkness, the same
law of respiration prevails as in organs destitute of chlorophyll, viz.
that the relationship between the volume of carbon dioxide given off
and that of oxygen absorbed is constant, whatever the temperature,
both increasing rapidly with rise of temperature.
Movements of the Sap in the Root-tubers of the Dahlia. —
K. Kraus has confirmed the remarkable observation that a tissue with
acid sap may exude an alkaline fluid or at least one that becomes ver
rapidly alkaline. The absorption of water by the tubers of the dahlia
takes place not at all or very slightly through the surface, but
almost entirely through the roots which are produced in abundance
in October and November. An abundant “ bleeding” or exudation
of sap takes place from uninjured leaves and from the axils of the
leaves ; also from transverse sections, which ceases as soon as the
tubers are deprived of their roots.
There is not in the tubers any sharp distinction between the
medullary rays and the xylem-parenchyma, the mass of the root con-
sisting mainly of rows of radially elongated parenchymatous cells.
There are, however, darker portions composed of tracheids surrounded
by a sheath of thick-walled parenchyma, corresponding to the “ fibre-
cells” of normal wood. When the tubers are cut off sap exudes
especially from the periphery of the xylem, most abundantly on
transverse and tangential sections, and proceeding mostly from the
closely inclosing parenchyma, partially also from the sieve-tubes and
pith. That which exudes from the sieve-tubes is alkaline, from the
wood and pith acid; inulin was also detected in it. The cause of
this exudation of sap the author regards to be tension of the tissues.
After the alkaline “bleeding” from wounded tubers has ceased, the
formation of cork commences on the wounded surfaces. The alkaline
reaction is probably the result of decomposition.
Absorption of Water by the Capitulum of Composite.t—A. Bur-
gerstein notices that the flowers of Composite possess the faculty of
absorbing water from without through the epidermis; and that the
under side absorbs water more rapidly than the upper side.
* Comptes Rendus, xeviii. (1884) pp. 1064-7.
+ Wollny’s Forsch. aus dem Geb, der Agricultur-physik, vi. (1884). See
Bot. Centraibl., xviii. (1884) p. 65.
t Ber. Deutsch. Bot. Gesell., i, (1883) pp. 367-70.
592, SUMMARY OF CURRENT RESEARCHES RELATING TO
Measurement of Turgidity.*—H. de Vries applies the term
“isotonic concentration” to the degree of concentration of different
solutions in which they attract water with equal force. The strength
of a solution of potassium nitrate, which has the same affinity to water
as the solution to be examined of any other substance, is termed the
“‘nitre-value” of that substance. Representing the attractive force
of a solution of potassium nitrate at 3, the numbers 2, 3, 4, or 5
might express that of other solutions. These numbers, representing
the attractive force for water of a molecule of the substance in ques-
tion in a dilute aqueous solution, are the isotonic coefficients of the
different substances.
The author describes in detail three methods of determining the
isotonic coefficients of a substance :—(1) The plasmolytic method, by
placing as similar pieces as possible of the tissue in solutions of
different concentration of the substance in question and of potassium
nitrate, and observing the degree to which the parietal protoplasm is
detached from the cell-wall. ‘This method can be applied in the case
of only a few plants. (2) The method of plasmolytic transport: by
measuring under the camera the plasmolysis which occurs on placing
the preparation in a solution of a salt which causes moderate plasmo-
lysis; then transferring to solutions of different concentration of
other salts, and again observing the plasmolysis. (38) The method by
tension of tissue, by observing the curvature of split terminal por-
tions of shoots in concentrated solutions of the substance to be
examined.
By turgidity the author understands the affinity of the dissolved
substance for water, and gives detailed results as to the proportion
of the turgidity due to the different constituents of the cell-sap, the
most important of these in this connection being sugar, oxalic acid,
and malic acid. Since the turgidity is constantly being changed by
substances out of which protoplasm is developed, the inquiry is one
of great importance in vegetable physiology. As a general rule, the
author finds the isotonic coefficients nearly to correspond for members
of the same chemical group.
B. CRYPTOGAMIA.
Cryptogamia Vascularia.
Origin of Roots in Ferns.j—Lachmann has studied the cauline
fibrovascular system of the ascending rhizome of Aspidium Filia-mas,
which forms a network of hexagonal meshes, from the periphery of
which spring the foliar and radical bundles. The former are from
five to seven in number, one, medio-dorsal, springing from the bottom
of the network, the others inserted symmetrically on its borders.
* Pringsheim’s Jahrb. f. Wiss. Bot., xiv. (1884) pp, 427-601; also Vers. Med.
K. Akad. Wetensch. Natuurk., xix. (1883) pp. 314-27, See Bot. Centralbl,,
Xvii. (1884) p. 170.
+ Comptes Rendus, xeviii. (1884) pp. 833-5.
ZOOLOGY AND BOTANY, MIOROSOOPY, ETO. 593
The radical bundles are always three in number, one median inferior
and two lateral, placed symmetrically on the lower half of the net-
work. The lower radical bundle always springs from the upper
extremity of a vertical bundle of the stem, inserted on its outer side,
almost always exactly in the middle, and often a little lower than the
medio-dorsal foliar bundle. From this point it rises obliquely in the
cortex, and after passing from 5 to 7 mm. bends, becomes thinner,
and goes out at the base of the petiole with the roots of which it
forms the central cylinder.
This inferior radical bundle is almost always absolutely inde-
pendent, but this is not always the case with the lateral radical
bundles. These latter have often a common point of departure with
the lower lateral foliar bundles, to which they may adhere for a
length varying from 2 to 4mm.; but the portion of this common
base which belongs to the radical bundle is generally clearly to be
distinguished from that which belongs to the foliar bundle, and some-
times the two bundles are altogether distinct from their insertion.
These lateral roots behave differently from the inferior root; after
an oblique course they pierce in the same way the cortex of the
petiole, the superficial layers of which form a cushion round their
base.
The examination of other ferns confirmed the view that in the
radical bundles we have a simple coalescence of two bundles originally
distinct.
In all Polypodiacez the adventitious roots spring from the cauline
network, and not from the base of a foliar bundle, even in those species
where, in the adult state, coalescence frequently occurs.
Monograph of Isoetee.*—L. Motelay and Vendryés publish a
monograph of the existing species of Isoetesw, founded on the mate-
rials left by Durieu.
Systematic Position of Lepidodendron, Sigillaria, and Stig-
maria.;—B. Renault maintains his previous view as to the relation-
ships of these fossil organisms, against the objections of Williamson
and Hartog. He considers that those Sigillarie which can be deter-
mined with certainty belong to the Gymnosperm type, while the
species of Lepidophlois have the characteristics of Lycopodiaces.
The Stigmariz must be regarded partly as rhizomes of Gymnosperms ;
the anterior portions must have had only leaves with monocentric
vascular bundles, the anterior part, after the fall of the leaves, only
adventitious roots with tricentric vascular bundles; while in the
middle were both roots and leaves. This may serve to explain the
conflicting descriptions of various writers.
* Actes Soc. Linn. Bordeaux, xxxvi. (1883) (10 pls.). See Flora, Ixvii.
(1884) p. 47.
+ Renault, B., ‘ Considérations sur les rapports des Lépidodendrons, des
Sigillaires et des Stigmarias, 32 pp. (1 pl.) 1883. See Bot. Ztg., xlii. (1884)
p. 139.
594 SUMMARY OF CURRENT RESEARCHES RELATING TO
Muscineze.
Variations in Sphagnum.*—C. Jensen discusses the causes of the
great disposition to vary displayed by the different species of Sphag-
num, and attributes it, in the first place, to the influence of water,
and secondarily to variations in the light, temperature, and in the
nature of the soil.
When the plant grows completely submerged, all the parts are
larger and longer; the stem-leaves become iarger, as also do their
hyaline cells, which are often provided with pores and spiral thicken-
ings; these leaves then resemble those of the branches in their
structure. Those branches which depend from the stem, forming an
envelope round it, lose this structure and grow like the other branches,
the fertile branches become longer, and are often inserted at a
greater distance below the apex of the stem; the bundles of the
branches stand at a greater distance apart.
Plants growing in a dryer situation are, on the contrary, more
compact, with shorter stems and crowded short erect branches with
closely adpressed leaves, as is especially seen in arctic forms.
When the moss grows in the shade it is of a brighter green and
stronger growth. 'The fertile branches may be inserted beneath the
apex of the stem, and are then somewhat elongated.
Forms sometimes occur with sickle-shaped branches, and others
which resemble the extra-Huropean species in having the stem-leaves
of nearly or quite the same structure as those of the branches. These
usually occur in dry places, but sometimes also in water.
Fungi.
Sexual Reproduction in Fungi.j—H. M. Ward gives an elaborate
résumé of the facts at present known respecting sexual reproduction
in the various classes of fungi. He points out that—at all events if
the Basidiomycetes are set aside—the absence of sexual organs
appears to be in direct proportion to the degree of parasitism deve-
loped by the fungus. There can be no doubt that the efficacy of any
act of impregnation depends on some essential difference in the nature
of the protoplasm of the two cells; that, in an oosphere, for example,
the molecular energy of the protoplasm is less than that of the rest of
the plant for the time being, and that the access of the antherozoid
reinvigorates the sluggish mass, causing the renewal of active life.
The dormant interval which frequently intervenes between impregna-
tion and germination may be occupied by molecular rearrangements
in the mass. The difference in the nature of the male and female
protoplasm is indicated by the attractive force which the female
frequently appears to exercise on the male element, as in the case of
Cidogonium. 'The reinvigorating effect of the male protoplasm may
last through many generations. The fact of the sexual organs having
* Bot. Tidsskr. Kjobenhavn, xiii. (1883) pp. 199-210. See Bot. Centralbl.,
xVii. (1884) p. 267.
t+ Quart. Journ. Micr. Sci., xxiv. (1884) pp. 262-310.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 595
partially or entirely disappeared in certain classes of fungi may be
explained on the hypothesis that the very strong development of their
parasitic character enables them to supply themselves abundantly
with food-material at the expense of the host, without any very great
consumption of vital energy, and thus renders unnecessary the re-
invigoration of the protoplasm, which is the main object of sexual
reproduction.
Life-history of Acidium bellidis DC.*—C. B. Plowright has
experimented on the A%cidium of the common daisy, and considers
that it is not a mere variety of Aicidium compositarum Mart., but a
true hetercecismal Uredine, differing from its allies in the time that
it appears.
Structure and Affinity of Spheria pocula Schweinitz.t|— Dr. M.
C. Cooke describes the structure of this species, and shows that it
must be relegated to the genus Polyporus, to which indeed it was
formerly referred by Berkeley and Curtis, though the fact appears
subsequently to have been forgotten.
Spheroplea.{—Under the designation var. crassisepta E. Hein-
richer describes a var. of Spheroplea annulina with thicker septa than
the ordinary form. Hematoxylin revealed the presence of a number of
nuclei in the cells, sometimes as many as 60, viz. from 1—4 in connection
with each ring of protoplasm. In the female cells a portion of the
protoplasm collects round each nucleus to form an oosphere, the
number of which therefore corresponds to the number of nuclei. The
formation of antherozoids is accompanied by a great and rapid
multiplication of nuclei, one nucleus being finally contained in each
antherozoid, The oospores germinated in the dark, producing swarm-
spores, from which new individuals sprung, but this latter germination
was dependent on the presence of light.
New Parasite on the Silver-fir.$—Under the name Trichospheria
parasitica, R. Hartig describes a parasitic fungus which has been for
some years very destructive to the pine-forests in the Neuburger
forest. The colourless mycelium attacks the young branches and the
leaves, covering the lower side with a weft of threads, and forming
blueish white cushions on both sides of the leaves, on which the
perithecia appear in autumn. ‘The black globular perithecia are
covered in the upper part with numerous long hairs, and have a
diameter of 0°1—-0°25 mm., or of 7 mm. including the hairs. The
asci are about 8:0 » in length, and completely disappear after the
ripening of the spores. The spores are smoke-coloured, usually
4-locular, straight, or somewhat curved, and from 15-20 » long. The
formation of the asci is preceded by that of very small rod-shaped
cells, possibly spermatia,
* Journ. Linn. Soc. Lond.— Bot., xx. (1884) pp. 511-2.
+ Ibid., pp. 508-11 (1 pl.). 4
t Ber. Deutsch. Bot. Gesell., i. (1883) pp. 433-50 (1 pl.). Cf. this Journal,
iii. (1883) p. 888.
§ SB. Bot. Verein Miinchen, No. 13, 1883. See Bot. Centralbl., xviii. (1884)
p- 62.
596 SUMMARY OF CURRENT RESEARCHES RELATING TO
Micrococcus prodigiosus within the Shell of an Egg.*—F. Ludwig
describes a hen’s egg the albumen of which was throughout of a rose-
red colour. The absorption-spectrum agreed altogether with that of
the colouring matter of Micrococcus (Monas) prodigiosus. The fungus
must certainly have been present in the albumen when in a raw state.
Photogenous Micrococcus.j{—F. Ludwig has identified the cause
of phosphorescence in fish with that of the less common phospho-
rescence of the flesh of animals used for food, especially swine. It
is due to a mucilaginous substance which can be readily wiped
off, consisting of micrococci in a state of active motion and
division, the characteristic form and arrangement of which are very
readily shown by pigments, especially gentian-violet. The zoogloea-
colonies are then seen to consist of sharply defined, roundish, densely
crowded cells, sometimes isolated, more often associated in beautiful
moniliform threads or compact colonies. The diameter of the cells
is about 0°5-1 p. To this organism Ludwig gives the name Micro-
coccus Pfliigeri. It can be readily transferred from the haddock or
other fish on which it is commonly found, to the flesh of oxen, calves,
sheep, swine, &c., producing in it the well-known phosphorescence ; it
occurs also naturally on crustacea, star-fish, &c.
On the surface of the sea is sometimes found a phosphorescent
slime, consisting largely of decaying organic matter, the phospho-
rescence of which is not due to Noctiluca or other animals of that
kind ; Ludwig attributes it also to this same species of Micrococcus.
Respiration of Saccharomyces.{—M. Paumés has investigated this
subject carefully, with the following results:—(1) The respiratory
activity of the ferment (S. cerevisie) decreases as the temperature
decreases; (2) in doses of from 1—2 per cent. ether has scarcely any
effect on the respiration; (8) in doses of from 3-6 per cent. ether
diminishes and even entirely stops the respiration ; (4) even by these
doses the plant is not killed.
Bacillus of Cholera.s—R. Koch has presented to the German
Government six reports on the cause of cholera-epidemic, as the result
of investigations on the excreta and on the dead bodies themselves of
cholera patients in Egypt and in India, and on the inoculation of
other animals with the germs. The internal organs, lungs, liver,
spleen, kidneys, &c., as well as the ejecta, were found to swarm with
microbia of a great variety of kinds; in all cases was found one
definite kind of bacillus, resembling in size and form that of
glanders. These were found in largest quantities in the tubular
glands of the intestines, especially between the epithelium and the
membrane of the gland. Experiments in inoculating other animals
with this bacillus yielded only negative results.
* Zeitschr. f. Pilzfreunde, 1883, p. 176. See Bot. Centralbl., xviii. (1884)
p. 161.
+ Hedwigia, xxiii. (1884) pp. 33-7.
{ Journ. Anat. et Physiol., xx. (1884) pp. 106-15.
§ ‘ Erster—sechster Ber. an den Staatssecretar des Innern iiber die Arb. zur
Erforschung der Cholera-Epidemie, von R. Koch.’ Alexandria-Calcutta, 1883-4.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 597
Observations on Egyptian ophthalmia showed that two different
diseases are ordinarily included under this name; one caused by a
kind of bacterium resembling the micrococci of gonorrhcea, the other
and less severe one by a very minute bacillus.
The experiments carried on in India determined the presence in
the intestines, in all cases of cholera, of the same bacillus as that
found in Egypt; and this Dr. Koch has been able to isolate and to
cultivate. It then furnished characters in its form and mode of
growth in nutrient gelatine, by which it is at once distinguished with
certainty from all other known bacilli. This particular form was also
never found in the intestines or in the ejecta of those not suffering
from cholera. Experiments on the infection with it of other animals
had not, up to the time of the publication of these reports, been
completely successful.
The cholera-bacillus is not quite straight, like most other bacilli,
but is somewhat curved, in the manner of a comma, or even nearly
semicircular. In cultivation there often arise S-shaped figures, and
shorter or longer slightly wavy lines. They are endowed with active
spontaneous motion. They can be best observed in a drop of nutrient
fluid attached to the cover-glass, which they are seen to swim through
in all directions. In gelatine they form colourless colonies, which
are at first close and have the appearance of small fragments of
glass, but gradually spread through the nutrient fluid. They have a
tendency to collect at the margin of the drop, where their peculiar
movements can be well observed, and their comma-like form after
treatment with anilin-solution.
As to the question whether their presence is simply due to the
presence of the choleraic disease which promotes their growth and
development, or whether they are themselves the cause of cholera,
Dr. Koch is very strongly of opinion that the latter is the true
explanation, since they are never found either in the organs or the
ejecta, except in the case of patients who have either died of or are
suffering from cholera. They are also found only in that organ
which is the seat of the disease, viz. the intestines. In the first
feculent ejecta, the bacilli occur only in small quantities; while in
the later liquid odourless ejecta, they occur in enormous quantities,
all other kinds of bacteria being almost entirely absent; they diminish
in number as the excreta become more feculent, and: have entirely
disappeared when the patient is completely restored to health. Their
abundance appears to correspond to the degree of inflammation of the
mucous membrane of the intestines, attaining their maximum when
this is of a bright-red colour, and the contents a colourless odourless
fluid. When the contents become offensive from effusion of blood the
bacilli decrease in number and are found only in the vesicular glands
and their neighbourhood. Where death results from a secondary
complaint following cholera, they are altogether wanting. Their
behaviour therefore closely resembles that of all other pathogenous
bacteria, their development being proportional to the severity of the
disease.
598 SUMMARY OF CURRENT RESEARCHES RELATING TO
Virus of Anthrax.*—In a preliminary communication, K. Osol
describes some experiments, performed in the Pathological Institute
of Dorpat, by which he claims to have proved that the bacilli which
occur in anthrax are only to be regarded as the secondary products
of a chemical virus.
Recounting the previous observations of Professor Semner and of
Rosenberger, who claim to have shown the same thing in septiczmia ;
he states that he himself, in “numerous experiments,” thoroughly
sterilized, by prolonged boiling, virulent anthrax blood, diluted with
an equal bulk of water, which was filtered; the residue again treated
with water, boiled and filtered; the filtrate from both, to insure
sterilization, was then boiled for two hours on three successive
days. Of this concentrated viscid anthrax virus, “large quantities ”
were injected subcutaneously into rabbits and mice, with carefully
disinfected syringes ; cultivations of sterilized bouillon were at the same
time inoculated each with “one drop” of the same superheated virus ;
and at the same time control-animals inoculated with small quantities
of the same, to demonstrate the absence of micro-organisms. As an
additional precaution, blood of healthy animals was treated in the
same manner as the anthrax blood, and similarly injected in large
quantities into rabbits and mice.
The animals inoculated with superheated anthrax blood died in
from 3 to 6 days; in about a fourth of the cases typical anthrax
bacilli were found in the blood and organs; in the other cases,
numerous micrococci, as previously found in anthrax blood by
Semner in 1871, and Bollinger in 1872, and shown by them to be a
phase of development of the typical bacilli, which has been quite
recently confirmed by Archangelski. The blood of animals killed by
inoculation with the superheated anthrax virus, when inoculated into
sterilized cultivating fluids, developed typical bacilli. Rabbits and
mice inoculated with it died of pronounced anthrax, in general with
numerous bacilli in the blood, or, in their place, micrococci and
“ diplococci,” which, cultivated, developed to anthrax bacilli. The
blood of these animals similarly was fatally infective.
In the control experiments, while animals inoculated with “small
quantities” of superheated virus remained perfectly unaffected,
cultivations inoculated with similar quantities continued sterile ; hence:
the author claims to have proved that in anthrax blood there is a
specific chemical poison, soluble in water, not volatile, of undetermined
composition, which, inoculated into other animals, so affects the tissues
of the organism that the innocuous microparasites normally present’
therein, develope under its influence, in from 3 to 6 days, to typical
anthrax bacilli in some cases, and in others to an earlier form of the
same.
The control-animals inoculated with superheated normal blood
were unaffected, save by a slight pyrexia. The author, as he states,
from these experiments, does not conclude that the bacilli have no
significance or action in anthrax, but, on the contrary, that they alone
* Centralbl. f. d. Med. Wiss., 1884, pp. 401-4.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 599
develope the anthrax virus in the living organism; though they are
not the primary but the secondary factor, and derive their virulence, in
the first instance, from the action of an unorganized chemical poison.
These conclusions are somewhat out of date at the present time,
and misleading. It has been proved to demonstration that in the case
_ of anthrax, the organism does, per se, constitute the active contagium.
The results obtained by Professor Rosenberger, referred to, have been
shown* to have been due to imperfect sterilization. In those here
described, the absence of infection with small quantities of the super-
heated virus, and its occurrence with large quantities, shows evidence
of the same phenomena; some germs or spores of the bacilli survived
the boiling, but these were too few in number to be infectious in every
small portion of the fluid, though they were so in large quantities.
Were a chemical poison, of which comparatively large quantities are
requisite, as asserted, the primary factor in infection, the micro-organ-
isms alone could never be active in unusual quantities, viz. in the
100-millionth of a drop (minim) as has been shown to be the case.
The final conclusion of the author here is an obvious paradox, viz.
that the micro-organism is at once both cause and effect; it alone pro-
duces the virus—a soluble chemical poison—and is produced by it.
Attenuation of Virus in Cultivations by Compressed Oxygen.t
—Experiments were made by M. Chauveau with compressed oxygen
on the bacilli of anthrax, to ascertain whether their virulence could
be modified by its graduated action, as by that of heat and other
agents; with the result, at first, that in the case of guinea-pigs the
cultivations of the organism exposed to its influence either became more
actively virulent at moderate pressures, or at high tension completely
inactive ; but with sheep, by the action of the agent, the cultivations
are modified in their virulence, so that it is not increased by moderate
pressure as with guinea-pigs, but on the contrary decreased ; and at
a point short of that which stops all development of the microbe,
spores are formed, which, though still fatal to guinea-pigs, are
innocuous to sheep.
At this stage of attenuation, however, they produce a temporary
affection, more or less pronounced, in all the sheep inoculated, which
passes off within a few days, and the animals are found to have
acquired immunity from subsequent infection with the most virulent
material; and that by the single inoculation.
This modification of virus is transmissible to cultivations of the
second generation, kept at 36-37° C. under normal pressure,
It is, too, very remarkable here, that though usually the blood
of guinea-pigs which have died of anthrax is fatally infective to sheep,
yet in the case of the former the blood of animals that have suc-
cumbed to inoculation with cultivations modified by pressure, is
innocuous to the latter, and moreover confers on them immunity from
future infection.
Further, these cultivations are so surely attenuated that no single
* Proc. Roy. Soc., xxxiv. (1882) p. 150.
+ Comptes Rendus, xeviii. (1884) pp, 1232-5,
600 SUMMARY OF CURRENT RESEARCHES RELATING TO
animal is killed by them, and the protection they confer is complete,
whilst they preserve their properties for several months, and are as
effectual with oxen as with sheep.
Cultivation of the virus of other diseases is equally modified by
compressed oxygen, as is notably that of swine fever (rouget).
In conclusion, the author trusts that this method of attenuating
virus, as yet only tried on a small scale in laboratory experiments,
may be rendered generally available in practice, with the immense
advantages it offers of (1) immunity conferred by a single inoculation,
with (2) perfect safety, and (8) the possibility of using the modified
cultivations a considerable time after their preparation.
Rabies.*—L. Pasteur, with the assistance of MM. Chamberland
and Roux, has a further | communication on this important subject.
1. if rabic virus is passed from a dog to a monkey, and then from
one to other monkeys, it gradually becomes weaker. If it is then
injected into a dog, rabbit, or guinea-pig, it remains in this attenuated
condition.
2. The virulence of the poison is increased when it is passed
from rabbit to rabbit, or from guinea-pig to guinea-pig. If in this
“ exalted” condition it is passed on to a dog it gives a rabies which is
always mortal in effect.
3. Although one can thus increase the virulence of the poison
by passing it from one to another rabbit, it is necessary to do so
several times if one is making use of a virus which has been attenuated
by a monkey.
Thanks to these observations Pasteur has been able to preserve
an organism from the effects of more active virus by the use of
that which is less so. Here is an example:—Virus, made more
powerful by passage through several rabbits, is inoculated into a dog,
but as it is inoculated into the dog at every stage of the experiments
on the rabbits, the result is that the dog becomes entirely refractory
to the poison of rabies.
Pasteur proposes to make the following experiments, of which the
first is the most decisive. He will take twenty of his “refractory ”
dogs and twenty that have not been inoculated; he will let all be
bitten by a “mad dog,” and he prophesies that his twenty will escape
the effects, while the other twenty will exhibit the influences of the
poison. A similar set of two twenties will be trepanned by the virus
of dogs & rage des rues; the twenty vaccinated dogs will resist the
poison, the others will die, either mad or paralysed. In a footnote
the author points out that of the twenty non-vaccinated dogs, or, as he
calls them, witnesses, all will not exhibit the effects of the poison to the
same extent, for rabies does not always follow on the bite of a mad dog.
Bacteria in Canals and Rivers.{—The much-discussed question as
to the purification of water in rivers “ by itself,” that is, by the mere
* Comptes Rendus, xcyiii. (1884) pp. 1229-31.
+ See this Journal, ante, p. 430.
t Nature, xxix, (1884) p. 557.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 601
fact of its motion, seems to have entered into a new phase. Dr. Pehl,
at St. Petersburg, has recently made a series of bacterioscopic
measurements on the waters of the capital, which are summed up in
the last issue of the ‘Journal of the Russian Chemical Society.” The
water of the Neva itself appears to be very poor in bacteria, namely 300
germs in a cubic centimetre. After heavy rains this number rises to
4500, and to 6500 during the thawing of the river. The canals of St.
Petersburg, on the contrary, are infested with bacteria, their
number reaching 110,000 in a cubic centimetre, even during good
weather. The same is true in regard to the conduits of water for the
supply of the city. While its chemical composition hardly differs
from that of the Neva (by which they are supplied), the number of
bacteria reaches 70,000, against 300 in the water taken directly from
the river; and the worst water was found in the chief conduit, although
all details of its construction are the same as in the secondary con-
duits. Dr. Pehl explains this anomaly by the rapidity of the motion
of water, and he has made direct experiments in order to ascertain
that. In fact, when water was brought into rapid motion for an
hour, by means of a centrifugal machine, the number of developing
germs was reduced by 90 per cent. Further experiments will show
if this destruction of germs is due to the motion of the mass of water,
or to molecular motion. The germs, among which Dr. Pehl distin-
guishes eight species, are not killed by immersion in snow. As
the snow begins to fall it brings down a great number of germs,
which number rapidly diminishes (from 312 to 52 after a three
hours’ fall of snow, on January 21st, 1884), while their number on the
surface of the snow increases, perhaps in consequence of the evapo-
ration of snow or of the condensation of vapour on its surface.
Bacteria from Coloured Fishes’ Eggs.*—Dr. Peter has investi-
gated the causes of various colouring of the eggs of Coregonus
Wartmanni, red, blue, and yellowish-brown, and finds it to be due to
the presence of bacteria, which frequently entirely filled up the
interior of the egg. The colour itself was due to drops of oil;
the bacteria themselves were always colourless, and of the following
kinds :—(1) slender smooth motile rods with short segments; (2)
thicker motile rods; (3) very thick, straight, smooth, motionless rods
(rare); (4) very slender, straight, smooth, motionless filaments ; (5)
micrococci. There was also not unfrequently a Saprolegnia present.
These bacteria were cultivated in a large number of different nutrient
fluids, when all transitions from them to a spirillum form appeared ;
as also a transition from the leptothrix form No.4, to aspirillum. A
transformation appears to take place of ordinary bacteria into those
which are the cause of the colouring of the eggs.
Bacteria connected genetically with Alge.t—H. Zukal has
continued his investigations { as to the genetic connection between
* Ber. Bot. Verein Miinchen, Sept. 19, 1883. See Bot. Centralbl., xviii.
(1884) p. 92.
+ Oecesterr. Bot. Zeitschr., xxxiv. (1884) pp. 7-12, 49-51.
t See this Journal, iii. (1883) p. 400.
Ser. 2.—Von., LV. 28
602 SUMMARY OF CURRENT RESEARCHES RELATING TO
Drilosiphon and Leptothriz, from which, in certain circumstances,
bacteria are produced. The filaments of Leptothrix muralis, which is
very common in greenhouses, forming a gelatinous deposit on the
walls, are usually of a light yellow colour; but when, as is frequently
the case, they grow among tne stems and leaves of mosses, they
gradually become green. It must therefore be assumed that there is
always in this species of Leptothrix a certain amount of green
colouring matter,—another illustration of the difficulty of drawing
an exact line of demarcation between the Schizomycetes and the
Schizophycee. It agrees with ordinary Schizomycetes in the capacity
for assuming bacterium, bacillus, coccus, and vibrio-forms ; and this
sometimes takes place even with filaments which are distinctly
reen.
: When a piece of pure leptothrix-jelly is cultivated under water
in a giass cell, hormogonia are soon separated, the time of their
appearance depending on the temperature of the water. These either
again develope into filaments, or pass into the bacterium form or,
finally, into the swarming condition. It is usually only the outside
filaments whieh project from the jelly that develope into hormogonia,
which either break through the mucilaginous sheath or escape through
its open end; on their escape they frequently display movements of
circumnutation, due to the contraction of the protoplasm and not
to the presence of cilia; the vibrio-form appears, however, to
possess cilia, though the author was not able to determine their
presence with certainty. The vibrio-form is developed only from a
few of the filaments at the margin of the jelly, presenting thus
a striking contrast to the true Schizomycetes, in which both the
vibrio and spirillum form-appear suddenly in large quantities, The
bacterium form of L. muralis exhibits an evident segmentation, espe-
cially after the application of dilute hydrochloric acid or potassium
acetate. The hormogonia, when they do not grow into filaments,
usually break up into bacteria, which then excrete a thick gelatinous
envelope, and swim on the surface of the culture-fluid, a zoogloea
family being slowly formed in this way. Less often the bacillus and
spirillum forms develope zoogloea colonies. Occasionally, by cell-
division within the jelly, the zoogloea acquires the habit of a palmella
or merismopezdia.
The presence of phycochrome is indicated by the motile hormo-
gonia always collecting on the illuminated side of the vessel. Under
certain conditions the bacteria swarm out of the zoogloea-jelly, leaving
their membrane behind; the cell-contents arrange themselves in a
direction at right angles to the original one, and may develope into
the bacillus, leptothrix, or spirillum form, then dividing into bacteria,
&c.; but in all the forms the representatives of the last generation
are always smaller than the preceding one, finally reaching the limits
of vision with the best immersion system.
In addition to the forms above described, Leptothrix muralis much
less often developes cocci, arranged in a moniliform string, often
interrupted by a large strongly refringent cell. Filaments are some-
times found which are segmented above into cocci, below into bacteria.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 603
The formation of cocci indicates a regression to the nostoe form,
which is also met with in the history of development of Drilosiphon.
Resting spores are formed here and there along with the cocci, from
1-1-8 » in diam.; and these occur also in the bacterium and vibrio
forms, in very long threads occasionally two.
The author concluded, as the result of experiments, that Lepto-
thriz muralis has no power of inducing fermentation or putrefaction.
The presence of free oxygen is absolutely necessary for its
growth. It is best cultivated in water containing traces of iron, lime,
and potash salts. It is probably capable of carrying on an inde-
pendent existence; but the presence of vigorous tufts of moss is
apparently favourable to its growth.
The micro-conditions of the three principal forms of Leptothria
muralis, the leptothrix form with its hormogonia, the nostoc form, and
the glceocapsa or palmella form, are morphologically altogether equi-
valent to true bacteria, but physiologically they are as widely
removed from them as any green plant from a non-chlorophyllaceous
saprophyte.
Action of Oxygen on Low Organisms.*—F. Hoppe-Seyler has
constructed an apparatus for the purpose of testing the influence on
the development of the lowest forms of animal life of an abundant
or restricted supply of oxygen. He finds that in the presence of free
oxygen the only certainly demonstrable products of the decomposition
of fluids containing albuminous substances are carbonic acid, ammonia,
and water. If the fluid is saturated with oxygen, neither hydrogen
nor marsh-gas makes its appearance ; the ordinary products of decom-
position, indol and skatol, are not formed at all, leucin and tyrosin
only temporarily. Microscopic examination shows that when decom-
position takes place in the presence of abundant oxygen, the Schizo-
mycetes are formed in much greater quantities than when the supply
of oxygen is small. The Schizomycetes and Saccharomycetes behave
in just the same way, from a chemical point of view, as all other
vegetable organisms, when supplied with abundance of oxygen; they
absorb oxygen, and give off carbonic acid, water, and ammonia, or
some nitrogenous substance nearly allied to it. In the absence of
oxygen all decomposing organisms display fermentation-phenomena ;
but while the Schizomycetes and Saccharomycetes can remain in this
condition for a considerable time, all other organisms perish rapidly
in the absence of oxygen. Certain Schizomycetes can sustain the
absence of oxygen for a considerable time, especially the one or more
species which split up cellulose into CO,, C Hy, and H,; but the
author altogether disbelieves the theory that there are organisms
which can exist only in the absence of oxygen.
Biology of the Myxomycetes.t—E. Stahl has made a long series
of experiments on the cause of the movements of the plasmodia of the
Myxomycetes, especially of Aithalium septicum. By causing one end
* Zeitschr. f. Physiol. Chemie, viii. (1884) p. 214. See Naturforscher, xvii.
(1884) p. 116.
+ Bot. Ztg., xlii, (1884) pp. 145-56, 161-76, 187-91.
os: 3
604 SUMMARY OF CURRENT RESEARCHES RELATING TO
of a piece of blotting-paper, the other end of which dips into water, to
come into contact with tan containing plasmodia of the Aithalium, he
found the latter to display the phenomenon of rheotropism,* i.e. they
move to meet the current of water, travelling in a horizontal or even
in a vertical upward direction. The same was observed with the
plasmodia of a small species of Physarum. The plasmodia display
not only rheotropism, but also hydrotropism, i.e. movements regu-
lated by the distribution of water in the substratum, when this water
is not in motion. During the greater part of the period of develop-
ment they display positive hydrotropism, or are attracted towards the
source of water. They are indeed very dependent on water for their
development. On a uniformly moist substratum in an atmosphere
saturated with moisture, they spread uniformly in all directions;
while in a dry air, when the substratum is gradually drying, they
contract, and Collect in the dampest spots. Negative hydrotropism
does, however, also occur, where the sporangia bend away from the
damp spots and stand erect ; this was observed, but only rarely, in
sporangia of Physarum, Didymium, and Afthalium.
Various chemical substances, such as crystals of sodium chloride,
nitre, cane-sugar, grape-sugar, drops of glycerine, &c., exercise a
repellent effect on the plasmodia. On the other hand an infusion of
tan produced an opposite attractive result; and to this property of
moving towards the spots where the supply of nutriment is most
abundant Stahl gives the name trophotropism. 'The same substance
may have opposite influences of attraction or repulsion according to
the degree of concentration of the solution.
As regards heliotropism, the author adds nothing to the facts
already known, that plasmodia move from illuminated spots to those
that are in shade. He was unable to determine satisfactorily their
relation to geotropism; the vertical position of the fructifications of
Myxomycetes appears to be due rather to hydrotropism than to
geotropism.
With respect to the effect of heat, if Athalium is exposed on the
two sides to unequal temperatures, an evident motion takes place
towards the warmer side.
Lichenes.
Cephalodia of Lichens.t—Pursuing this subject, K. B. J. Forssell
states that the alge found in connection with cephalodia belong to
all the groups of Phycochromacee, including the following families:
—Nostocacez, Sirosiphonew, Scytonemacee, Chroococcacer, and
Oscillariacer, the first being the most largely represented. The
Nostoc cells take up very different positions in relation to the gonidial
layer of the thallus, belonging to the different kinds of cephalodia
already described. Occasionally several species of alge are found
in the same cephalodium.
The development of cephalodia is always the result of the mutual
* See this Journal, ante, p. 413.
t Flora, Ixvii, (1884) pp. 33-46, 58-63, 177-87. Cf. this Journal, ante, p. 100.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 605
action of hyphe and algal cells; it is not a true parasitism, since the
alge are not destroyed or weakened by the fungal hyphe ; nor can it
be regarded as a true example of hypertrophy of the algal cells.
There is no struggle for existence between alge and hyphe. The
author was unable to detect the mode in which the algal cells pene-
trate into the thallus, but each seems to impart nourishment to the
other.
The author regards cephalodia as always the result of an acci-
dental meeting of alga and lichen, the former constituent always
belonging to a type of very wide distribution ; but there must also
always be some power of adaptation of one to the other; some forms
of lichen, as Cladonia, appear never to form~cephalodia. If
Schwendener’s hypothesis is regarded as one of mutual symbiosis of
algee and fungi, rather than as one of parasitism, then the occurrence
of cephalodia supports it rather than otherwise.
Thallus of Lecanora hypnum.*—kK. B. J. Forssell describes the
somewhat peculiar structure of the thallus of this lichen. It consists
of an incrustation of small yellowish-brown rounded granular scales,
which do not form a continuous layer, but the whole lichen consists
of a complex of individuals more or less cohering in their growth.
The scales are of two kinds, one with yellow-green, the other with
blue-green gonidia. The author is doubtful whether the latter are
to be regarded as cephalodia, or as belonging to a different lichen-
species, Pannaria pezizoides. Apothecia occur, on the under side of
which are sometimes cephalodia containing cells of a Nostoc.
Alge.
Systematic Position of Ulvacee.j—The third part of J. G.
Agardh’s series of Monographs of Algz is devoted to the Ulvacez. |
Differing from Berthold’s view,t he places the genera Bangia and
Porphyra among the Ulvacez, and not among the Floridee. In this
he relies chiefly on the difference of the reproductive organs in the
Ulvacee and Floridex, the former possessing true zoospores, the
Floridew antheridia, cystocarps, and tetraspores. The quaternate
division of the cells in the two genera in question he regards as
showing an affinity not so much with the tetraspores of Floridex, as
with the mode of division in Prasiola, Tetraspora, Palmella, Mono-
stroma, and some species of Ulva and Enteromorpha. There is also a
very material difference in their physiological value, the octospores
of Porphyra being regarded as sexual, the tetraspores of the Floridee
as non-sexual. ‘here is at present a very considerable divergence
between the description by different writers of the organs of repro-
duction in Bangia and Porphyra.
The Ulvacesw are divided by Agardh into eleven genera :— Gonio-
trichum, Erythrotrichia, Bangia, Porphyra, Prasiola, Mastodia, Mono-
* Flora, Ixvii. (1884) pp. 187-93.
+ Agardh, J. G., ‘Til Algernes Systematik ? Lunds Arsskrift, xix. (4 pls.)
(Latin). See Nature, xxix. (1884) p. 340,
t See this Journal, iii, (1883) p, 408,
606 SUMMARY OF CURRENT RESEARCHES RELATING TO
stroma, Ilea, Enteromorpha, Ulva, and Zetterstedtia. Of these,
Mastodia and Zetterstedtia are natives of the southern ocean ; Ilea is
represented bya single species, I. fulvescens, growing at the mouths of
some Swedish rivers.
Newly-found Antheridia of Floridee.*—T. H. Buffham briefly
sums up what is known concerning the reproduction of the Floridez,
and gives more particular descriptions of the antheridia of species
not figured by Harvey.
In Callithamnion tetricum the antheridia appear to be almost
terminal, and the principal portion of the mass is on the inner face
of the ramulus, which in the specimen figured is bent down by its
weight. Call. byssoideum has antheridia that are quite hyaline, with
the exception of the cellules forming the axis. The antherozoids are
very elongated, and their attachment can scarcely be made out. In
Call. Turneri the antheridia cluster thickly on the ramuli, and are of
ellipsoidal form, colourless, and filled with antherozoids. The
antheridia of Call. plumula are ramose, and occur in clusters, all
rising from one cell of the ramulus.
In Griffithsia corallina the antheridia cluster round the filament
at the junction of two cells.
Figures of the foregoing, as well as of the antheridia of Ptilota
elegans, Ceramium diaphanum, and C. strictum are given by the author.
New Unicellular Alge.{—P. Richter describes the following
‘new species of Alge (or Protophyta) :—Protococcus gemmosus, in
greenhouses, allied to P. cinnamomeus; Dictyospherium globosum ;
Aphanocapsa Naegelii, in greenhouses ; Aphanothece nidulans, an
extremely minute species, in greenhouses, along with Protococcus
grumosus ; Oscillaria scandens, also in greenhouses, possesses a strong
smell, somewhat resembling patchouli; Scytonema Hansgirgianum,
in similar situations, allied to S. Hofmanni; Nostoc Wolluyanum.
The author states further that his Aphanothece caldariorum is the
bacillus-form of Glaucothrix gracillima Zopf, and is probably identical
with Aphanocapsa nebulosa A. Br. and Gleothece inconspicua A. Br.
Structure of Diatoms.t—Count Castracane gives a very useful
epitome of the chief points in the structure and different modes of
reproduction of diatoms.
Belgian Diatoms.§—Dr. H. van Heurck has published the first
two sets (including fifty species) of slides illustrating his Synopsis
of Belgian Diatoms, determined and described by A. Grunow. The
specimens are, for the most part, preserved in the fluid composed and
described by van Heurck, compounded of styrax and liquidambar,
which has a higher index of refraction than Canada balsam ; || a few
in solution of phosphorus.
* Journ. Quekett Micr. Club, i. (1884) pp. 337-44 (8 pls.).
+ Hedwigia, xxiii. (1884) pp. 65-9.
{ Castracane, Conte Ab. Francesco, ‘Generalita su le Diatomee,’ 12 pp.
Roma, 1884.
§ Van Heurck, H., ‘Types du Synopsis des Diatomeées de Belgique,’ Serie i.
ef ii. Anvers, 1883.
|| Infra, p. 655,
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 607
Diatomacee from the Island of Socotra.* —F. Kitton gives a list
of twenty-two fresh-water species from the Island of Socotra.
Amongst these are a new species of Cerataulus (C, Soctrensis), which
is the first fresh-water representative of the genus, and Fragilaria
Ungeriana Grun., which has previously been found in only two
localities— Cyprus and Belgaum (India).
——
MICROSCOPY.
a Instruments, Accessories, &c.
Microscope with Amplifiers.—Fig. 89 shows’ two methods of
applying a series of amplifiers to the Microscope :—(1) A disk contain-
ing four apertures is mounted
above the nose-piece to rotate Fi. 89.
so as to bring the apertures
successively into the optic axis.
One aperture is blank for
normal examinations; and the
others are provided with bi-
concave lenses of 3 in., 4 in.,
and 5 in. negative focus re-
spectively. This application
of amplifiers was exhibited at
the Society several years ago,
but we have not succeeded in
tracing the name of the ex-
hibitor. (2) Mr. J. Mayall,
jun., suggests that the ampli-
fiers should be mounted in a
plate (shown in the fig. ) sliding
through the body-tube, and
with means of raising or lower-
ing it within the body-tube so
that the best position with each
objective may be found experi-
mentally.
The use of such amplifiers ;
involves a slight deterioration
of the quality of the image, but
in many cases this would be
more than compensated by the
increase in the magnification
and in the working distance.
Bausch’s Binocular Microscope.t—The following is E. Bausch’s
specification of his “ Binocular Microscope ” :—
‘My invention relates to the class of Microscopes in which part
of the rays of light emanating from the object and passing through
* Journ. Linn, Soc. Lond.—Bot., xx. (1884) pp. 513-5 (1 pl.).
t Specification of U.S.A, Patent No. 293,217, dated February 12th, 1884.
608 SUMMARY OF CURRENT RESEARCHES RELATING TO
the objective are divided by a doubly reflecting prism, known as the
‘Wenham prism,’ so that one-half of the rays pass to an auxiliary eye-
piece mounted in a branch tube applied to the side of the main tube.
In Microscopes of this class the prism has heretofore been mounted
in a box arranged to slide laterally in the lower part-of the Microscope-
body, so that it could be moved into and out of its place by sliding
the box, and any imperfection in the bearings of the box, which are
necessarily narrow, allowed the box to move laterally, thereby impair-
ing the effectiveness of the instrument. Another serious objection
to the common method of mounting the prism is, that the size of tubes
in Microscopes being limited, and the box being contained entirely
in the tube or nose-piece, the movement of the box and size of the
prism are correspondingly limited. This being the case, a large
proportion of the rays which are transmitted by modern objectives
are prevented from passing to the eye-piece, so that it has frequently
been found necessary to remove the nose-piece containing the ordi-
nary prism-box and replace it by another nose-piece which had no
obstruction when the full effectiveness of the objective was desired.
__ My invention is designed to obviate these difficulties by pro-
viding a prism-holder with a long cylindrical bearing, which is
readily made and practically indestructible by wear, and which admits
of either binocular or monocular arrangement of the Microscope
with the full effect of either method of vision.
It consists of a prism-carrying arm fixed to the end of a spindle
extending through a sleeve passing through the side of the Microscope-
body, the spindle being provided with a milled head, by which it is
turned, and with a stop-pin, for limiting its motion.
Fig. 90 is a vertical section on the line « a in fig. 91 of a portion
of a Microscope-body, showing my improvement applied. Fig. 91 is
a plan view, partly in section.
The body of the Microscope is provided with a nose-piece A,
threaded in the usual way at its lower end to receive an objective, and
having sufficient depth to contain the prism-holder B. The prism-
holder B consists of a metallic plate a, bent twice at right angles,
and receiving between its parallel sides b c the prism C. The side ¢
of the holder B is prolonged, forming an arm c‘ which is secured in
any suitable manner to the end of a spindle D. In the present case
it is fitted to a shoulder on the spindle and fastened by means of a
small nut d fitted to the threaded end of the spindle. The spindle
D is fitted to a sleeve KE, passing through the side of the nose-piece
A, so that it may turn therein without lateral or longitudinal motion.
To insure the perfect bearing of the spindle D in the sleeve E the
sleeve has a longitudinal slit e, which permits it to adapt itself to
the spindle by springing and to create the small amount of friction
necessary to retain the prism-holder in any position. The outer end
of the spindle D is provided with a milled head F, by which the
prism may be moved into or out of the field, and a pin /, projecting
from the spindle through a slot g in the sleeve EH, limits the motion
of the prism-holder in either direction. The prism-holder B is
arranged relative to the main and auxiliary tubes of the Microscope
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 609
so that it will swing in a plane lying in the axes of the two tubes,
and when it is swung down into the position shown in full lines in
the drawings the prism intercepts one-half of the rays passing
through the objective and diverts them to the auxiliary tube. When
Fie. 90.
the Microscope is used for monocular vision, the prism is turned out
of the field, as indicated by dotted lines in fig. 90.
Having thus described my invention, what I claim as new, and
desire to secure by letters patent, is—
1. In a binocular Microscope, a swinging prism-holder adapted
to support the prism within the body of the Microscope either in or
out of the field of vision, as herein specified.
2. The combination, with the doubly reflecting prism of a bino-
cular Microscope, of a prism-supporting arm and spindle attached
thereto, and extending outward through the Microscope-body, as
described.
3. The combination, in a binocular Microscope, of the prism C,
prism-holder B, spindle D, provided with the stop-pin jf, and the
slotted sleeve E, as herein specified.”
Sohncke’s Microscope for Observing Newton’s Rings.*—This
instrument (fig. 92) is a device of Dr. L. Sohncke for examining
Newton’s rings, and it is claimed that it fulfils all the conditions in
regard to variety of movements (and their measurement) necessary in
such an instrument.
The microscope-tube (provided with cross threads and magnifying
20 to 25 times) slides in a short socket H, the former having a scale
in half-millimetres (with a nonius on H) for allowing the exact
position to be read off. The socket, with the Microscope, can be
turned on a horizontal axis, fixed in the front part of two brass
* Zeitechr. f. Instrumentenk., i. (1881) pp. 55-8 (1 fig.).
610 SUMMARY OF CURRENT RESEARCHES RELATING TO
shoulders h, rising from a common base plate. On one side the axis
carries a quadrant turning with the Microscope, and having one
arm parallel with the optic axis of the Microscope. A plumb line
gives the angle on the quadrant. On the other side of the axis is
a serew-nut to clamp it in any desired position. The brass base plate
to which the shoulders h are attached, slides by means of a screw M,
in a second piece shown in the figure. The motion is at right angles
to the plane of incidence of the light falling on the object, i. e. from
right to left (or vice versd) as the observer would stand in using the
instrument. The second piece is again part of another slide, which
Fic. 92.
“a
Ca?
(oa |
i oa HAAG A | |
is moved backwards and forwards by the screw M,; the motion here
is at right angles to that of the first slide, and therefore parallel to
the plane of incidence. The extent of these two movements is read
off on two millimetre scales on the guides of the slides, and the
screw heads are divided for reading fractional parts of mm. The
heavy iron base G of the whole instrument rests upon three feet,
and the plane and convex glasses g are laid upon a small stage T
attached to the front of the instrument, and capable of being raised
and lowered above G as required.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 611
Although the apparatus in this form may be thought to fulfil all
requirements, Dr. Sohncke considered it especially necessary to add
an additional contrivance for indicating, without further measure-
ment, the most characteristic phenomenon in the position of Newton’s
rings, viz. that those ring-points which are in the plane of incidence
passing through the centre of the rings, all lie in a straight line
which rises obliquely towards the light. The greatest inclination of
this “fundamental line” towards the horizon is 19° 28’. If we have
an arrangement by which the Microscope with any angle of incidence
can be given a movement parallel to the “fundamental line,” then
when any one ring (in the central plane of incidence) is clearly seen
by proper focusing of the Microscope, all the rings in succession will
also be clearly seen by the movement in question ; whilst if the Micro-
scope were moved horizontally, they would very soon be out of focus.
This requirement is carried out in the present instrument by the
guides of the lower slide being fixed, not upon the horizontal base G,
but upon the plate P, which is movable on an axis at right angles to
the plane of incidence, and can be fixed at any required inclination
between 0° and 20°. That the object may not be disturbed by the
inclination of the plate, it is cut out somewhat in the shape of a
horse-shoe. To use this arrangement the plate P must be placed at
the angle w» of the “fundamental line” for the particular angle of
incidence 6. The value of w is obtained from the formula :—
sin @ . cos @
tgwo=
The Microscope is then to be placed at the required angle of
incidence. In order to do this direct, a plumb line, instead of an
index, is used for reading off the “angle” on the quadrant, as an
index would join in the inclination of the plane P. The lower
slide has now only to be moved parallel to the plane of incidence, by
means of the screw M.,, in order to see all the rings pass across the
field in complete distinctness.
Dr. J. H. L. Flégel describes* a method of determining the thick-
ness of diatoms by the examination of the Newton rings formed when
they are illuminated by reflected light from a Lieberkiihn, It con-
sists simply in tilting the slide at an angle, the light being admitted
to the Lieberkiihn through a small excentric aperture in the dia-
phragm, reaching the objective only after reflection from the prepara-
tion.
Harris & Son’s Portable Microscope.—This (figs. 93 and 94) is
a somewhat ancient form, probably fifty years old, but is arranged
on an ingenious plan to secure portability. When set up for use it
takes the form shown in fig. 93. By unscrewing the tube, and
screwing it into the lower side of the ring which holds it, and closing
the tripod legs together, it is reduced to the form shown in fig. 94.
* Arch. f. Mikr, Anat., vi. (1870) pp. 472-514,
612 SUMMARY OF CURRENT RESEARCHES RELATING TO
The subsidiary leg, which carries the mirror, folds against the leg
of the tripod to which it is attached. The stage is removable, leaving
Fie. 93.
Last
ine —_—
FN
a ring, which is attached by three supports to the tripod, and rises
and falls somewhat as the tripod legs are shut or opened.
The instrument is hardly so convenient as the modern forms which
Fig. 94.
have been devised in such profusion, but it is interesting as being a
very early progenitor of this class of instrument.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 613
Seibert’s No. 8 Microscope,—The Micro- Fig. 99.
scope No. 8 in Seibert and Kraft’s Catalogue i
(fig. 95) has a fine adjustment similar in
principle to those described Vol. III. (1880)
p. 882, though carried out in a different man-
ner. Here the stage is supported on a horse-
shoe-shaped frame, and is pivoted to one of
the projecting arms. A screw passing through
the opposite arm raises the stage at the end
and as the screw is withdrawn a spiral spring
presses the stage back again.
Reichert’s Large Dissecting Microscope
and Hand Magnifiers—C. Reichert’s large " |
dissecting Microscope (fig. 96) is of excep- ag
tional size for the examination of sections of — =
brain and similar large objects. The stage
is entirely of glass, and is 11-5 cm. wide and
18 cm. long. The mirror can be moved for-
wards and to both sides. The preparation is
intended to be fixed while the lens is capable
of being moved over it in all directions. The
arm a b can be rotated on a, and the lens-
carrier c d can also be rotated at b. By turning
the milled head « the inner tube d which carries
the lens is pushed forward or withdrawn again.
614 SUMMARY OF CURRENT RESEARCHES RELATING TO
Herr Reichert also mounts two doublets of 10 and 20 power in a
nickelled frame (fig. 97, natural size). When not in use they are
Fig. 97.
ie REICHERT WIEN 2
—
IML
turned back within the frame, or for examining an object, brought out
as shown in the fig.
Geneva Company’s Dissecting Microscope.—This, fig. 98, con-
sists of two parts, a support for the lenses and a stage and mirror.
The two are quite separate, a plan which gives more freedom of action
than can be obtained in the ordinary form of dissecting Microscope.
The lens-support can be raised by a pinion acting on a rack on an
inner tubular pillar. It can also be rotated in a horizontal plane on
the top of the latter or in a vertical plane on the pivot clamped by the
second (upper) milled-head.
The stage has side rests for the hands and can be screwed to the
top of the box holding the instrument. The mirror is rotated on its
axis by the milled-head shown on the right. On one side there is an
ordinary concave mirror and on the other a plane one of opal glass.
Drallim and Oliver’s Microscope Knife— The following is taken
from the advertisement of this knife (fig. 99) :—
“ It comprises a great variety of articles including a large dagger-
blade, small penknife, pair of folding scissors, corkscrew, nail-trimmer
and file, tortoise-shell toothpick and ear-scoop, nickel silver tweezers,
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 615
and last, but by no means least, a very powerful Microscope. We are
not aware of any other knife manufactured which contains a Micro-
scope of any description, and we anticipate an enormous demand in
consequence. An ordinary pocket handkerchief submitted to the
lens of this powerful glass, the texture appears nearly as coarse as a
sack. Scientific students and merchants will find this invaluable to
them, as the knife is of convenient size to be carried in the waistcoat
pocket.”
Ward's Eye-shade.*—Dr. R. H. Ward’s device consists (fig. 100)
of a circular disk of hard rubber or blackened metal, about 14 in. in
diameter, an extension of which in the form of a band 1/2 in. wide
crosses in front of the nose of the observer, but quite out of the way,
and encircles the top of the
draw-tube or compound body Fic. 100.
just below the ocular. As now
used, this shade is made of hard
rubber, which is of light weight,
and suitably dark colour, is
less likely than metal to
scratch the brasswork with
which it comes in contact, and
is so elastic as to be applicable to a considerable variety of tubes.
The same shade, for instance, can be used on tubes of from 1 to 1} in.,
or from 1/8 to 13, the best fit being of a size midway between the two
extremes. Besides this easy range of adaptation, this eye-shade differs
from those hitherto in use in its attachment to the body instead of
the ocular, by which it is brought to an advantageous distance from
the face, and is retained in position as long as the instrument is in
use, instead of being removed with the ocular and requiring a fresh
application every time that is changed. It is reversible by simply
turning it over, and can thus be instantly transferred from the left
* Amer. Mon. Micr. Journ., y. (1884) pp. 82-3 (1 fig.).
616 SUMMARY OF CURRENT RESEARCHES RELATING TO
to the right eye, according to the observer's custom of using either
eye habitually or both in succession. It is equally applicable to
stands whose construction does not admit of its being slipped over the
tube from the top; the spring ring at the right of the figure being
in such cases made partly open so as to spring on from the side.
Endomersion Objectives.*—Prof. K. W. Zenger claims to have
found that perfect achromatism of telescope and Microscope objectives
is possible by using a mixture of ethereal and fatty oils, the dispersive
power of which for the different rays of the spectrum increases regu-
larly. The disadvantages of the use of fluids are obviated by mixing
with suitable salts of the fatty acid series by which nearly hard or
gelatinous, vitreous, homogeneous, colourless, and transparent sub-
stances are obtained.
The following are extracts from two papers published by the
author :—
The construction of achromatic objectives for telescopes, M’<cro-
scopes, and photography has, from the beginning, presented great diffi-
culties theoretically as well as practically. The dioptrical formule
which give the equations for the achromatism and aplanatism of the
objectives are so complicated that, up to the time of Fraunhofer and
the younger Herschel, opticians were content with developing the
conditions of achromatism and aplanatism in the axis. In this way,
however, a perfect objective was theoretically not to be obtained, and
therefore the best makers of that time were obliged to confine them-
selves to experimental trials.
Herschel and Fraunhofer first showed the way to a more accurate
determination of the direction of the rays, and the former has given
us a complete theory of telescope objectives, but for the much more
difficult computation of Microscope objectives almost nothing has
been done, and we to-day still look for a theory of these objectives.
The principal practical difficulty for all kinds of objectives lies in
procuring suitable refracting media, because the flint and crown glass,
hitherto exclusively used, deviate greatly from the conditions of
perfect achromatism. Blair, at the end of the last century, showed the
possibility of getting rid of all colour by the use of at least three
refracting media, crown glass, oil of turpentine, and naphtha, which
give contrary secondary spectra, the dispersive power of one being
greater in the red, and of another in the violet part of the spectrum.
In this way he succeeded in making an absolutely achromatic
objective, the aperture of which was particularly large, namely, one-
third of the focal length.
After Blair the matter was lost sight of until the second decade
of the present century, when Barlow made an objective of crown
glass and a biconcave lens filled with bisulphide of carbon on the
dialytic principle. The achromatism of this was not, however,
perfect, Blair’s use of more than one fluid not having been attended
to, and the question again fell into oblivion.
* SB. K. Bohm. Gesell. Wiss. Prag, 1881, pp. 479-92, 467-79 (reversed in
order).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO, 617
Prof. Zenger, in view of Blair’s experiments, determined to see
whether it would not be possible to find fluids which in combination
with crown glass, would produce achromatic objectives. The con-
ditions for absolute achromatism require that the partial dispersions
should maintain the same relation in all parts of the spectrum for the
two refracting media. Now mixtures of aromatic and fatty substances
possess this property to a high degree of approximation, so that when
combined as lenses with crown glass (a biconvex crown and a plano-
concave fluid) all the different rays of the spectrum will be united
and a perfection of achromatism will be produced not hitherto
attained.
The question of course arises whether the fluids. in consequence
of striz-formations, through rapid changes of temperature, may not
originate a new element of optical imperfection. This is opposed to
the author’s experience of fluid achromatics in sunlight, either with
the telescope or Microscope. He has succeeded in converting the
ethereal and fatty oils which serve for the production of the refract-
ing media, into the condition of vitreous bodies, or into a kind of
gelatine in which striz-formation is not as easily possible as in very
mobile fluids.
By solutions of stearic, oleic, or palmitic acid, or mixtures of
these, we can change benzol, castor-oil, poppy-oil and other similar
ethereal and fatty oils into transparent gelatine, which is amorphous
like glass, perfectly clear and does not flow out of the vessel if in-
verted. These substances are already used in the arts.
An immense scope for combination is thus opened in order, so to
say, to produce kinds of glass of any desired refraction and dispersion,
and consequently the optician is saved the trouble of undertaking
changes of radius at great expense and loss of time. It is sufficient
to make a suitable selection of the gelatine substance which is to
be inclosed between a plane parallel plate and the biconvex lens, in
order to solve the hitherto difficult problem of a perfect achromatic
and aplanatic lens-combination.
The closing up of the fluid must be as hermetical as possible, in
order to prevent any evaporation and chemical change in the course
of time. There are ethereal and fatty oils which are transparent and
very little changeable.
The problems as to lenses for telescopes, Microscopes, and photo-
graphic objectives are therefore, it is claimed, extraordinarily
simplified through the use of “endomersion” objectives, which are
thus named by the author in analogy with immersion objectives,
because the fluid is between the lenses. On account of the fact that
three radii are equal, while the fourth is infinitely great, he also
calls them “symmetrical” endomersion objectives, a quality which
embraces the most favourable conditions for brightness, sharpness,
and flatness of field of view.
Formule and tables are given for the construction of endomersion
objectives, and after considering more particularly the case of teles-
cope objectives, those for the Microscope are dealt with, in which case
the plane side of the concave fluid lens should be turned to the object.
Ser. 2,—Vou, LV. 2T
618 SUMMARY OF CURRENT RESEARCHES RELATING TO
Such an objective is then somewhat over-corrected, and thus exactly
suited for a Microscope objective, because in the case of a single lens
the over-correction can be removed by the Huyghenian ocular, while
with doublets and triplets, the lens can be corrected or over-corrected
to the desired amount, the residue being removed by the ocular as is
commonly done by the Lister method. :
When the necessary calculation for a given mean refractive and
dispersive relation, such as from quartz to a fluid, is once made for a
fixed large angle of aperture and a given thickness of the lens, it is
easily seen what alterations a change in the refraction of. the less
refracting lens requires, according to the crown glass used, and we
can correct the objective accordingly.
An objective, composed of three achromatics, whose curves were
calculated for parallel rays (according to the formule and tables of
the author) gave such satisfactory results that further detailed
calculation is only required for exceptionally large angles of aperture.
The performance of a triplet of 8 mm. equivalent focus composed
of three symmetrical endomersion lenses consisting of crown glass
and a mixture of fatty and aromatic substances, gave perfect achro-
matism, for when achromatic eye-pieces (by Schréder) were used
which magnified 9, 18, 36, and 72 times, there was even with the last,
in bright lamplight and sunlight, scarcely a trace of colour on
diatoms or on a Zeiss’s silver grating, whilst all the objectives at
hand * showed all the colours of the spectrum with such enormous
eye-piece power.
With some of these objectives, however, the aplanatism was more
perfect than others, which can probably be accounted for by slightly
imperfect centering of the three lenses, and also by the defective
quality of the plane-parallel plates, in place of which, later on, con-
cave lenses of great focal length were used.
In direct light, with an angle of aperture of only 56°, all the
more easy diatoms of Moller’s plates were resolved, and of the more
difficult the following :—Fhabdonema arcuatum and R. adriaticum,
Achnanthes subsessilis, Scoliopleura convexa (the images appear black
upon white).
With oblique light :—WNitzschia circumsata, Navicula divergens, N.
minor, Gomphonema geminatum, Melosira Borrerit, Symbolophora Trini-
tatis, Odontodiscus subtilis, Hyalodiscus stelliger, and H. subtilis could
not be quite resolved, as they were on the limits of the unresolvable
with the aperture. Grammatophora marina and Pleurosigma angu-
latum were not resolved.
A double symmetrical endomersion objective, combined after the
manner of Steinheil’s “ Symmetric Aplanaten,” gave no trace of a
difference of the chemical and visual foci, and therefore such an
objective, which can be constructed from quartz and a very transparent
fluid, is of practical importance for photography.
The usual contrivance is not necessary for obtaining sharp photo-
graphs of diatoms, which will even bear well a power of 30 times as
* Objectives by Schneider of Berlin, 1” to 2” dry, and 3—+,, (sic) immersion,
by Zeiss 1 n (A) and Hartnack, as well as Reichert of Vienna.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 619
microscopic objects, furnishing the best proof of the coincidence of
the optic and actinic foci. The eye-piece is removed and the camera
placed in position, without having to make use in any way of coloured
or subdued light for the illumination.
In an abstract * of Prof. Zenger’s papers by G. Fischer, he expresses
the apprehension that the unavoidable changes of temperature to
which the lenses would necessarily be subject would be likely to im-
pair their efficiency, and adheres to his own view that absolute
achromatism will in all probability only be obtained by the discovery
of more favourable kinds of glass.
Prof. Zenger subsequently wrote t to Herr Fischer that Merz’s
crown glass is still much wanting as regards refraction and disper-
sion; in his view crown and flint never give a rational dispersion,
although flint containing different quantities of lead approximates
to it. Incomparably better is the achromatism obtained by his fluid
lenses, which are as much in advance of the best achromatics of the
present time as these latter are in advance of the non-achromatics.
The analogy of the eye, which formerly led to the discovery of
partial achromatism, prompted him to try and obtain absolute
achromatism by imitation of the gelatinous fluids of the eye, that is
by mixing two, three, and four different fluids. In this he has
succeeded ; two or three fluids, oil and balsam mixed, give, compared
with crown glass or quartz, quite rational spectra; that is constant
ratio of the partial dispersions. A constant dispersion-quotient can
be obtained for the whole length of the spectrum within 0:002 to
0-004, therefore much better achromatism than with the best of
Merz’s systems, in which the quotients differ from 0°004 to 0°026.
Finally he points out that the experiences of photography suffice
to show how much the best productions of the first modern opticians
fail in collecting all the rays to one focus. He, on the contrary, is
able with his fluid system to obtain micro- and astrophotographs
without the interposition of coloured glasses or adjustment-correction,
just as if his lenses were mirrors ; consequently, all rays, chemical and
optical, are united in one focal point.
Prof. Safarik has pointed out { to Herr Fischer that whilst with
Zenger’s objectives perfect achromatism is undoubtedly almost attain-
able, yet it is very doubtful whether aplanatism (removal of spherical
aberration) is also attainable. With Merz the diminution of the
dispersion-relation necessarily entails a lengthening of the focus, the
reverse of what opticians have hitherto striven to obtain. ‘‘ Whether,”
adds Herr Fischer, “ Zenger’s system, the three-lens system (Merz’s),
the improved Herschel-Fraunhofer system with more perfect kinds of
glass, Pléssl-Littrow’s, or an entirely new system, attains the desired
end, this much may, 1 consider, be confidently expected, that sooner
or later a considerable improvement of the achromatism, and with it
of the optical capacity of the Microscope and telescope, will be assured,
In conclusion, I gladly avail myself of the opportunity of bringing
* Central-Ztg. f. Optik u. Mech., iv, (1883) pp. 254-6,
+ Ibid., p. 267.
t Ibid.
272
620 SUMMARY OF CURRENT RESEARCHES RELATING TO
forward the opinion of so competent a judge as Dr. L. Dippel,*
against that of Prof. Merkel, who has objected to Merz’s object-
glasses that they get dim from being too soft. Dr. Dippel writes: ‘I
have lately become more closely acquainted with Merz’s objectives,
1/3, 1/9, 1/12, 1/18, and 1/24 in., and have convinced myself that
the objection made to them by Prof. Merkel of their being affected
by the air is not well founded.’ ”
Selection of a Series of Objectives—At p. 449 (last line but
one) a misprint occurs of 200° instead of 120° as in Dr. Carpenter’s
original text.
Correction-Adjustment for Homogeneous-Immersion Objectives. t
—Dr. W. B. Carpenter’s views on this somewhat vexed question
are explained in his article ‘“‘ Microscope’ in the ‘ Encyclopedia
Britannica.’
After pointing out that with homogeneous-immersion objectives
the microscopist can feel assured that he has such a view of his object
as only the most perfect correction of an air-objective can afford,
Dr. Carpenter continues as follows: “This is a matter of no small
importance, for while in looking at a known object the practised
microscopist can so adjust his air-objective to the thickness of its
cover-glass as to bring out its best performance, he cannot be sure, in
regard to an unknown object, what appearance it ought to present,
and may be led by improper cover-correction to an erroneous conception
of its structure.
“Tt has been recently argued that, as the slightest variation in
the refractive index of either the immersion fluid or the cover-glass,
a change of eye-pieces, or the least alteration in the length of the
body—in a word, any circumstances differing in the slightest degree
from those under which the objective was corrected—must affect the
performance of homogeneous-immersion objectives of the highest
class, they should still be made adjustable. The truth of this con-
tention can, no doubt, be proved, not only theoretically, but practi-
cally, the introduction of the adjustment enabling an experienced
manipulator to attain the highest degree of perfection in the exhibition
of many mounted objects, which cannot be so well shown with
objectives in fixed settings. But it may well be questioned whether
it is likely to do the same service in the hands of an ordinary working
histologist, and whether the scientific investigator will not’ find it
preferable, when using these objectives, to accept what their maker
has fixed as their point of best performance. The principal source of
error in his employment of them lies in the thickness of the optical
section of the object ; for the rays proceeding from its deeper plane,
having to pass through a medium intervening between that plane and
the cover-glass, whose refractive and dispersive indices differ from
those of the glass and immersion fluid, cannot be brought to so accurate
a focus as those proceeding from the plane immediately beneath the
cover-glass. The remedy for this, however, seems to be rather in
* ‘Das Mikroskop,’ 2nd ed., 18838, p. 460.
+ Encyclopedia Britannica, 9th ed., xvi. (1883) p. 265.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 621
making the preparation as thin as possible than in the introduction of
what is likely, in any but the most skilful and experienced hands, to
prove a new source of error. Every one who has examined muscular
fibre, for example, under a dry objective of very high power and large
aperture, well knows that so great an alteration is produced in its
aspect by the slightest change in either the focal adjustment or the
cover-correction that it is impossible to say with certainty what are
the appearances which give the most correct optical expression of its
structure. This being a matter of judgment on the part of each
observer, it seems obvious that the nearest approach to a correct view
will be probably given by the focal adjustment of the best homogeneous
immersion-objectives, in fixed settings, to the plane of the preparation
immediately beneath the cover-glass.”
Lighton’s Immersion Illuminator.*—This device of W. Lighton
(fig. 101) consists of a small disk of silvered plate-glass c, about 1/8 in.
thick, which is cemented by glycerin or some homogeneous-immersion
medium to the under surface of the glass slide s, r being the silvered
surface of the disk, b the immer-
sion objective, and / the thin glass Fic. 101.
cover. The ray h from the
mirror or condenser above the
stage will enter the slide, and
thence be refracted to the sil-
vered surface of the illuminator r,
whence it is reflected at a corre-
sponding angle to the object in
the focus of the objective. A shield to prevent unnecessary light from
entering the objective can be made of any material at hand by taking
a strip 1 in. long and 3/4 in. wide, and turning up one end. A hole
of not more than 3/16 in. in diameter should be made at the angle.
The shield should be placed on the upper surface of the slide so that
the hole will cover the point where the light from the mirror enters
the glass. “ With this illuminator Méller’s balsam test-plate is
resolved with ease, with suitable objectives. Diatoms mounted dry
are shown in a manner far surpassing that by the usual arrangement
of mirror, particularly with large angle dry objectives.”
Illumination by Daylight and Artificial Light—Paraboloids and ~
Lieberkiihns.t—E. M. Nelson finds daylight effective for low powers
up to 2/3 in., and with condenser up to 1/6 in. Direct sunlight
involves the use of a heliostat, otherwise the continued adjustment
of the mirror is irksome. Where strong resolving power is needed,
oblique pencils of sunlight from the heliostat outrival any other
illumination ; but much care is necessary not to injure the sight, and
on the whole, he cannot recommend its general use except for photo-
graphing. Diffused daylight is too uncertain and too variable for
accurate testing of objectives. It is not possible to get with diffused
daylight the absolutely best image that an objective will produce.
[]%
* Amer. Mon. Micr. Journ., vy. (1884) pp. 102-3 (1 fig.).
+ Engl. Mech,, xxxix. (1884) p. 48.
§22 SUMMARY OF CURRENT RESEARCHES RELATING TO
A really critical image could only be seen with artificial light, and
with a good condenser and diaphragms. He does not mean to say
that no good work can be done with diffused daylight, for excellent
work is done with low or medium powers; but he insists that it is not
possible to do any such critical work as testing objectives by daylight
as thoroughly as it can be done by artificial light. With daylight and
mirror only there is milkiness and “ glaze.” 'The milkiness can be
got rid of by a diaphragm, and the “ glaze” by using a ground glass
behind the object. Unless a condenser is used there will always be
found a falling off in the quality of the image with all powers higher
than 2/3 in. From long experience in working with the Microscope,
he feels justified in asserting that on the whole daylight is more trying
to the sight than lamplight.
The oxy-hydrogen light may be serviceable for resolving such
tests as Nobert’s lines, but the incandescence lamp he regards as
entirely a failure for microscopical purposes. “This is at once
obvious upon the consideration that the finest images seen are got by
viewing objects, as it were, in the image of the source of light. All
critical images of transparent objects viewed by direct transmitted
light require first that the source of light should be pictured by the
condenser exactly in the plane of the object, the object then serves
to interrupt the image of the source of light. The observer has simply
to arrange the lamp, condenser, and diaphragms so as to produce the
most perfect image of the source of light of the required size in the
plane of the object, the objective will then have fair play. The size
of the image of the lamp flame can be controlled by distancing the
lamp. There is no other secret in the matter. With the incandescent
lamp the image produced by the condenser represents the mere
carbon thread, on which no object could be seen projected ; in order
to obtain some extent of brightly luminous field, the condenser must
be put out of focus, then the intensity of the light is so reduced that
the observer would simply discard the incandescence, finding it far
less serviceable than a shilling paraffin lamp.”
He entirely condemns the use of paraboloids for dark-ground
illumination, as properly adjusted central stops with the condenser
will give by far the best dark-ground illumination. For opaque
objects he considers nothing has been devised so good as Lieberkiihns,
and objects ought as far as practicable to be mounted for use with
Lieberkiihns, and not covered up with paper. If the side illuminator
is used it should be attached to a fixed part of the stand, not to the
body-tube or stage.
With the preceding remarks may be contrasted the view of
Prof. Abbe (in litt.) that it is quite immaterial, from a theoretical
point of view, whether an illuminator has or has not spherical
aberration. The effect of illumination does not depend upon the
projection of a sharp image of the source of light upon the object, nor
even on the projection of any image at all. The only object of pro-
jecting an image of the source of light approwimately at the plane
of the object is in order that a uniform illumination of a given area
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 623
of the object (the field of vision) may be obtained by means of a small
source of light. This object is attained notwithstanding considerable
aberrations, and it is the better obtained the greater the focal length
of the illuminating system. A lens of 3/4 in. curvature is therefore
less advantageous than one of 1 in.
The general view of English microscopists is undoubtedly in
favour of the superiority of an achromatic condenser over any non-
achromatic arrangement. With the latter, confused pencils of light
are produced by the spherical aberration, which seriously impair the
images of fine structures, whilst with the former, “the most delicate
objects are seen with a clearness and sharpness of detail quite
unknown to those microscopists whose experience has been confined
to the use of non-achromatic condensers.” *
Bausch’s New Condenser.{—E. Bausch describes a new condenser
(figs. 102 and 103), similar to thaf of Prof. Abbe, the formula upon
Fie. 102. Fie. 108.
i
T TTT |
‘nT
Tl
which it is constructed being, however, a modification of that used in
Bausch’s Immersion Illuminator. The posterior system is as large
as the substage-ring will allow, and will transmit and condense all the
rays which pass through thisfrom the mirror. Its numerical aperture
is about 1-42.
There are two styles of mounting, fig. 103 shows the substage
adapter and condenser with a swinging diaphragm ring between them.
This ring receives the various stops, which may be changed without
disturbing the condenser. Fig. 102 is intended to give the different
degrees of oblique illumination, from central to that of the utmost
possible limit. It is provided with a circular opening, 1/4 in. in
diameter, which may be decreased if desired, and which is caused to
move slowly from the centre to the edge of the mounting by turning
the outside milled edge.
Both of these mountings are adapted to substages attached either
to the substage bar, or fixed to the bottom of the stage. The condenser
is also furnished with plain substage adapter only.
Glass Frog-plate.—This (fig. 104, designer unknown) is a simpli-
fication of the ordinary frog-plate. The general form of the
* Swift’s ‘ The Microscope,’ 1883, p. 43.
+ The Microscope, iy. (1884) pp. 105-6 (2 figs.).
624 SUMMARY OF CURRENT RESEARCHES RELATING TO
old brass plates is retained, but in place of brass glass is used, the
edges of which are serrated for the string. The brass pin is at
Fie. 104.
present only cemented to the plate; it would be better if it passed
through it.
Groves and Cash’s Frog-trough for Microscopical and Physio-
logical Observations.—Some years since Mr. J. W. Groves devised a
simple guttapercha trough, in which circulation in the webs of frogs
could be observed for a considerable time without the web becoming
dry. This was efiected by keeping the feet of the frog entirely
covered with water, into which the objective (protected by a water-
tight cap closed below by a piece of thin glass) could be lowered
after the fashion of Mr. Stephenson’s submersion objective. This
contrivance he and Dr. Theodore Cash have considerably improved.
The trough (fig. 105) is long enough to admit a full-sized frog ; in
Fic. 105.
_——
Men
U
the bottom, which is lined with cork, are two windows of glass, through
which light may be transmitted to the webs of the feet. At the
anterior end is a projection, with a cork bottom and glass window for
the examination of the tongue, and another similar projection at the
side for the observation of the mesentery or lungs. The trough is
made of vulcanite, and is watertight, but at the posterior end is a
sliding piece by which that end can be opened and a thread passed
through to the lever of a myograph. In convenient situations are
binding screws for the connection of wires from a coil or battery.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 625
Hither or both of the projecting portions of the trough can be shut off
from the main receptacle by sliding hatches (not shown in the fig.)
if necessary, and the part containing the body of the frog can be
covered with glass or a vulcanite lid. Should it be desired to observe
the effect of gases or of heat or cold, the required gases or warm
or cool air may be conducted through the body chamber by means
of the two small tubes seen projecting from the front and sides
respectively.
The frog to be observed is placed either ventrally or dorsally as
may be required, and is held by means of loops of thread passed
round the arms and then led through screw-eyes and clamped up.
The thighs are held by a pair of stocks, which, by means of a sliding
upper half, can be adjusted accurately to the limbs without causing
constriction ; and the webs are spread out by pinning loops of thread
tied to the toes.
Visibility of Ruled Lines.*—C. Fasoldt writes, in regard to the
-note by Professor W. A. Rogers, which appears at p. 489 of vol. iii.
(1883), that “there are some statements which do not agree with my
experience. I find that lines properly ruled on glass are similar to
graven lines; they are smooth, clean cut, having a definite shape and
depth. Such lines are always visible in the Microscope, and central
or oblique light will show the bottom of each cut as a dark or
coloured line, plainly visible, and requiring no graphite or other
foreign substance to indicate it. The Microscope is the test for a
properly ruled line. The mechanical elements (pressure, &c.) enter-
ing into the process of ruling are not at all evidences that lines have
been properly ruled. The slightest accident to the point of the
cutter, or the surface of the glass not being perfectly clean, will spoil
a line; that is, produce a scratch which cannot be satisfactorily
illuminated in any light. Well-ruled bands of lines, 70,000 or
80,000 to the inch, are visible in the Microscope with central light ;
and with a Smith vertical illuminator (giving central light), I have
seen 100,000 lines to the inch. As these individual lines have a
width of about 1/200,000 of an inch only, it follows that the difficulty
is not to see such a narrow line, but to eliminate the diffractions
which tend to blur the image in the Microscope, and so prevent the
resolution or separation of the lines in a band of them.”
Mercer’s Photomicrographic Camera.t-——Dr. F. W. Mercer has
devised the camera shown in fig. 106. It consists of a box of light
wood A, a cone of light metal B, a tube which takes the place of the
ordinary draw-tube of the Microscope, C, and the frame carrying the
ground glass and plate-holder, D. The tube C is fitted to the cone
B, so that it may be withdrawn for the insertion of an eye-piece or
amplifier. To the box A is attached a brass strap a, the lower end
being slotted to admit the passage of a binding screw secured to a
button b, fastened to the arm of the stand. As soon as the object
is coarsely focused upon the ground glass the cone and its tube are
* Scientific American, xlviii. (1883) p, 341.
¢ ‘ Photography’ (Chicago), i. (1884) pp. 9-10 (1 fig.).
626 SUMMARY OF CURRENT RESEARCHES RELATING TO
raised slightly, say about a quarter of an inch from the body of the
Microscope, and the binding screw is then tightened, securing the
weight of the camera, &c., upon the arm of the instrument, thus
removing any undue pressure upon the rack and pinion, or fine move-
ment of the tube, during future manipulation. The fine focusing
Fic. 106.
when completed leaves nothing to be done but to push the ground-
glass frame on till it is replaced by the plate-holder, when the picture
may be made.
The features claimed for this apparatus are: “Its great porta-
bility, measuring when the draw-tube has been removed from the
cone, 44 x 41 x 9 in.; its ready application to the Microscope
in any position from the vertical to the horizontal, requiring but a
few minutes for its adjustment without changing the position or light,
at least for moderate powers; its special fitness for the amateur, being
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 627
moderate in first cost and inexpensive in use from the size of the
plate used. Though the plate is small, 3} x 4 in. (lantern size), it
is very useful and will meet most of the needs of the amateur workers
for whose convenience the instrument is intended.
There is a class of work of which this little camera is incapable,
and in introducing it to the notice of microscopists, it is not intended
to convey the impression that it will supersede other means where
skilled hands and elaborate apparatus are absolutely necessary. To
those who have but an hour or two of an evening for observation with
the Microscope, this camera may prove of service in securing a photo-
graph quickly at the work-table.
The box above the cone might be dispensed with, and the slide
carrying the ground glass attached directly to the large end of the
cone. The advantage in having the box is the shutter, which may be
fitted to its interior for excluding light from the plate at the moment
of completing the exposure, a preferable means to that of placing a
piece of black paper between the objective and the source of light.
Instead of having the ground glass and plate-carrier in one frame, it
might be desirable for some to have them separate, having more than
one plate-holder. The apparatus can at a trifling cost be attached to
most stands, and when properly made should not exceed, including
ground glass and plate-holder, seven or eight ounces in weight.”
Photographing Bacillus tuberculosis.*—M. Defrenne describes
the process which he adopts to photograph this Bacillus with a Tolles’
1/10 in. (hom. imm.), without eye-piece, using extra rapid bromo-
gelatine plates, developed with ferro-oxalate, a petroleum lamp being
employed for illumination.
If, he says, the determination of the actinic focus of objectives
constitutes, so to say, the chief difficulty in photographing ordinary
microscopic preparations, it is no longer so when we deal with
organisms so infinitesimally small as the bacilli of tuberculosis.
Here arises a difficulty of quite another kind, which at first seemed
insurmountable: the staining of the bacilli by means of fuchsin.
This agent, even when it is employed in thick layers, is somewhat
actinic, and it becomes the more so as the object stained is smaller or
more transparent. These two circumstances are combined in the highest
degree in the organisms in question. Thus at the beginning the
plates exposed were either uniformly acted on or the image was so
faint and so little differentiated after development that they were
worthless for proofs on glass or on paper.
These negative results suggested the abandonment of the attempt,
when the idea was suggested of having recourse to the use of a com-
pensating glass of a colour complementary to red (that is green), placed —
between the objective and the sensitized plate. By thus filtering the
image formed by the objective, the red rays, the only ones passing
through the bacilli, are absorbed, if not wholly, at least in great part.
The microbes therefore appear nearly black on the plate, and make
* Bull. Soc. Belg. Mier, x, (1884) pp, 128-32.
628 SUMMARY OF CURRENT RESEARCHES RELATING TO
a much slower impression than the rest of the preparation, which
gives free passage to all the green rays. More contrast is thus
obtained and a very distinct photograph produced.
Beck’s ‘‘Complete ’’ Lamp.—For pathological and physiological
investigation, as also for many other branches of microscopical
Fia. 107.
1
|
if
|
i
i
|
i
Hi
i
|
i
|
i
|
|
Sart
Samet oe ma,
ole
ole
a
research, a lamp more delicate in its adjustments and giving a
greater control over the light than those ordinarily in use is requisite,
and Messrs. Beck have therefore constructed a lamp whereby more
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 629
perfect illumination of both opaque and transparent objects can be
obtained.
The base A (fig. 107) consists of a heavy ring, into which a square
brass rod B is screwed. The square rod carries a socket C with an
arm D, to which the lamp is attached. This socket fits the square
rod loosely, but is kept in any position by a lever HE, which is
pressed firmly against the square rod by a strong spring. If the
lever and the opposite side of the socket are taken between the
thumb and finger, the pressure of the lever on the bar is removed,
and the lamp can be raised or lowered to the desired position, when
by releasing the hold the lamp is at once clamped.
On each side of the burner, and attached to the arm D, is an up-
right rod G, to one of which the chimney is fixed, independent of the
reservoir of the lamp, but fitting closely over the burner, thus
enabling the observer to revolve the burner and reservoir, and obtain
either a thin intense light or a broad and diffused one, without alter-
ing the position of the chimney. The chimney F is made of thin
brass, with two openings opposite to each other, into which slide
3 x1 glass slips of either white, blue, or opal glass, the latter serving
as a reflector.
The reservoir, although holding enough oil to burn for several
hours, is made very flat, and drops into the annular base, thereby
bringing the flame of the lamp within 3 inches of the table, render-
ing it much more serviceable for direct illumination (without the
mirror) and for other purposes.
A semicircle swings from the two uprights G, to which it is
attached by the pins H, placed level with the middle of the flame ;
to this semicircle is fixed a dovetailed bar L, carrying a sliding
fitting O, which bears a Herschel condenser P.
This condenser, swinging with the middle of the flame as a centre,
is always at the same distance from it; and thus, when once focused,
needs no further alteration for any change in the inclination of the
beam of light. The condenser is fixed at any inclination by a milled
head working in a slotted piece of brass K, fixed to the arm D.
When used for transparent illumination, the condenser is not
required below the horizontal position ; but when the lamp is re-
quired for the illumination of opaque objects, the chimney having
been temporarily removed and the milled head fixing the condenser
arm having been loosened, the arm with the condenser can be thrown
over the lamp, as shown in the illustration at M, and the chimney
being replaced, the light, which now comes through the opposite
opening of the chimney, can be condensed at a large angle below the
horizontal.
James’ ‘ Aids to Practical Physiology. *—It is beyond our com-
prehension how this extraordinary book could ever have been written
by an author entitled to add M.R.C.S. to bis name, or published as a
volume of ‘Students’ Aids Series’ by such publishers as those whose
* J. Brindley James, M.R.C.S., ‘ Aids to Practical Physiology,’ 8vo, London
(Bailliere, Tindall, & Cox), 1884, viii. and 60 pp.
630 SUMMARY OF CURRENT RESEARCHES RELATING TO
names are attached to the title-page, which moreover bears the motto
‘Mens sana in corpore sano.” That we do not criticize it without
reason will be seen by the following extract which is prefaced by the
statement that it contains a “few practical hints which we trust may
“powerfully tend to facilitate the young experimentalist’s labours.”
The italics are ours.)
“The Microscrope (sic).—You cannot expect to get one of any
valuable power (!) under five guineas. It should be of two powers,
enabling you to use inch and quarter-inch glasses(!) The hole in
the stage should have its awis diametrically consistent (!) with that of
the tube of the instrument. A stand is also needed (!!) Object-glasses,
denoted as one-fourth, one-fifth, one-sixth, are used for high powers,
one-half to two-fifths (!) for low. An oil-immersion lens is now-a-days
a necessary complement, and should be about one-twelfth. The
simpler it is the better for a beginner(!) The same may be said of
the eye-piece (!!) With respect to such other adjuncts as achromatic
condensers, special stands, &c., these concern the accomplished micro-
scopist rather than the tyro.”
As it was obvious that the author was not at home in the optical
branch of his subject, we turned to the description of a piece of
apparatus with which the practical physiologist should necessarily be
intimately acquainted—the Microtome. Will it be believed that it is
described not as an instrument for cutting sections, but for freezing
specimens! The author’s own words are as follows: “'The Micro-
“tome. This useful device for freezing specimens is susceptible of
“ various forms of construction.”
After these extracts it is superfluous to refer to the other minor
blunders which disfigure the book, such as the description of Dr. Klein
as “Klean,” the indiscriminate use of “bichromate of potash,”
“ pnotass ” and “ potassium,” and “ potassic bichromate” for the same
p 2
substance.
Postal Microscopical Society.—This society is now forming a
section specially devoted to members of the medical profession (in-
cluding students).
“A PRESIDENT.”—Suggestion for making the ‘ Journal of Microscopy’ the Journal
of provincial and other Microscopical Societies.
Journ. of Micr., III. (1884) pp. 194-5.
‘* AMATEUR.”’— Bacteria and the Microscope.
[Elementary Inquiries. | Engl. Mech., XXX1X. (1884) pp. 465-6.
American Society of Microscopists, Session of 1884.—Circulars of President
J. D. Cox, and E. H. Griffith. - Micr, Bull., 1. (1884) pp. 25 and 28.
Amer, Mon. Micr. Journ., VY. (1884) pp. 117-8.
The Microscope, IY. (1884) p. 133.
BELFIELD, W. T.—Photo-micrography in Legal Cases. [ Post. ]
Photography (Chicago); I. (1884) pp. 54-9 (7 figs.).
Brappury, W.—Papers relative to the theory of the Object-glass.
[Note introducing paper by Dr. C. S. Hastings, from ‘ Amer. Journ. Sci.,’
detailing the method used by him to determine the optical properties of
various kinds of glass and the alterations in the properties when the
glass was subjected to different temperatures. ]
Engl. Mech., KXXIX. (1884) pp. 420-1.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 631
Butiocu, W. H.—The Congress Nose-piece.
(Further rejoinder to Prof. McCalla’s claim of priority. }
Amer. Mon. Micr. Journ., V. (1884) pp. 119-20.
Carnoy, J. B.—La Biologie Cellulaire. Etude comparée de la cellule dans les deux
Régnes. (Cellular Biology; a comparative study of the cell in the two
kingdoms.) Fase. I. 271 pp. and 141 figs. 8vo, Lierre, 1884.
[Part I. Microscopical Technics (pp. 37-167, 24 figs.). 1. On instruments
and the laboratory of the microscopist or cytologist. 2. On objects and
their preparation. 3. On the method to be followed in microscopical
observations and cytological researches. ]
CARPENTER, W. B.—Article “Microscope” in the ‘Encyclopsdia Britannica,’
9th ed., XVI. 4to, Edinburgh, 1883. [Cf ante, pp. 448 and 620.]
Cox, J. D.—See American.
sx Photographs showing the structure of Diatom shells.
Amer. Mon. Mier. Journ., V. (1884) p. 112.
D., E. T.—Graphie Microscopy. VI. Pupaof Locust, oneday old. VII. Cluster
Cups: Zcidium quadrifidum.
Sci.- Gossip, 1884, pp. 121-2 (1 pl.), 145-6 (1 pl.).
DEFRENNE.—Présentation d’une Microphotographie du Bacillus tuberculosis.
(Exhibition of a photomicrograph of Bacillus tuberculosis.) With remarks by
E. yan Ermengem. ([Supra, p. 627. ]
Bull. Soc. Belg. Micr., X. (1884) pp. 128-32.
Dun ey, Prof.—Microscopic Photography:
[Response to a toast. ] Photography (Chicago), I. (1884) pp. 71-2.
Ermencem, E.—See Defrenne.
F.R.A.S.—Optical Recreations.
(Containing a note on the convex lens used as a magnifying glass. |
Knowledge, VI. (1884) pp. 46-7 (4 figs.).
Francotre, P.—Aspirateurs pour tenir constamment saturee d’air l’eau des
récipients ot l’on observe les animaux et les plantes aquatiques. (Aspirators
for keeping saturated with air the water of receptacles for observing aquatic
animals and plants.) (Post. ] Bull. Soc. Belg. Micr., X. (1884) pp. 141-3.
Giant Electric Microscope.
[Criticism of its defects.] Journ. of Sci., VI. (1884) p. 370.
Git, D.— Article “ Micrometer” in ‘ Encyclopedia Britannica,’ 9th ed., XVL.,
p-. 248. 4to, Edinburgh, 1883.
[Contains “ How to web a filar micrometer.” Post.]
Gowen, F. H.—Resolution of Amphipleura.
[Direct sunlight above the stage. ‘The Microscope should be so placed
that the light may fall on the circumference of the stratum of immersion
fluid obliquely to the upper surface of the slide, and care should be
taken to have one end of the frustule point towards the sun.”
Amer. Mon. Mier. Journ., V. (1884) p. 118.
iy ef Resolution by Central Light.
(Resolution of A. pellucida in balsam by sunlight with the mirror in a strictly
central position. ‘The resolution was effected by light reflected within
the slide from one of its convex edges, and that instead of being central
the light was very oblique.” ]
Amer. Mon. Micr. Journ., V. (1884) pp. 118-9.
Grirrits, E. H—See American.
Harpy, J. D.—Microscopical drawing.
[Report of demonstration.]} Journ. Quek, Micr, Club, I. (1884) pp. 360-1.
Hastines, C. 8.—See Bradbury, W. :
Haziewoop, F. T.—A home-made revolving table.
[‘‘I got a second-hand sewing-machine table . . . Then I took another
table-top which was raised about 2 in. from the other by a moulding.
On the top of the first table I put a piece of pine board 1 in. thick. Into
this I put three small castors upside down. I bored three holes in the
top of the other table, on radii, from acommon centre. Then I put top
No. 2 over top No. 1, 80 that the castors came over the surface about 1/4 in.
632 SUMMARY OF CURRENT RESEARCHES RELATING TO
Through the centre of both tables I bored another hole. Then I took
a steel saw-plate into which the teeth had not been cut. I hada hole
bored in its centre, and two brass handles or pins put in opposite each
other near the circumference. This plate is fastened by a pin with nuts
on the table over the three castors. The table is perfect. I painted the
steel plate. The drawer of the first table on the side serves for accessories.
The whole thing cost less than five dollars. The finished table looks as
though made for this purpose, and not for a sewing-machine.”’]
Amer, Mon. Micr. Journ., V. (1884) p. 94.
Herricz, S. B—The Wonders of Plant Life under the Microscope. 248 pp. and
85 figs. 8vo, London, 1884.
Hertwic, O.— Die Verwendung des Sciopticons als eines Anatomischen
Unterrichtsmittels. (The employment of the Sciopticon for anatomical
instruction.)
[Exhibition of glass photograms and sections. ]
SB. Jenaisch. Gesell. Med. § Naturwiss., 1883, p. 17.
Hevurcs, H. Van—[Protest against the review of his ‘‘ Lumiere électrique,” by
Stein, in ‘ Zeitschr. f. Wiss. Mikr.’]
Journ. de Microgr., VIII. (1884) pp. 273-7.
Hircucocn, R.—The Postal Microscopical Club.
[Exhortation to put better slides in the boxes. ]
Amer. Mon. Micr. Journ., V. (1884) pp. 113-4.
James, F. L.—The St. Louis Microscopical Society.
| Notification of its formation. ] The Microscope, 1V. (1884) pp. 129-30.
James, J. B.—Aids to Practical Physiology. viii. and 60 pp. 8vo, London, 1884.
[ Supra, p. 629.]
Liguton, W.—Immersion Illuminator. [Supra, p. 621.]
Amer. Mon. Micr. Journ., V. (1884) pp. 102-3 (1 fig.).
Mosivus, K.—Rathschlage fiir den Bau und die innere Hinrichtung zoologischer
Museen. (Advice on the construction and internal arrangement of Zoological
Museums.)
[Contains a reference to the ‘‘ Microscopirzimmer. ”
Zool. Anzeig., VII. (1884) pp. 378-83.
Mu uer, P.—Insectenfanger mit Lupe. (Insect-catcher with lens. Post.)
German Patent No. 25,806, 6th June, 1883. See
Zeitschr, f. Instrumentenk., IV. (1884) pp. 259 (1 fig.).
Neson, E. M.—How to Work with the Microscope.
[Report of demonstration. See ante, pp. 447 and 464. The view originally
expressed as to the decided preference to be given to the Ross form over
the Jackson is modified. “In point of steadiness he did not think there
was much to choose between them in first-class stands.”
Journ. Quek. Micr. Club, I. (1884) pp. 375-9.
5 * The Health Exhibition. \
[Description of Microscopes, Apparatus, &c., exhibited. ]
Engl. Mech., XX XIX. (1884) pp. 437-9.
Rogers, W. A.—On a practical solution of the perfect screw problem.
[Describes the method by which it is claimed a perfect screw can be made
on a commen lathe, including a Microscope provided with Tolles’ opaque
illuminator attached to the carriage moved by the leading screw of the
lathe. ]
Engl. Mech., XX XIX. (1884) pp. 341-2.
Royal Microscopical Society: Notes as to the admission of ladies and rearrange-
ment of the Cabinet. Journ. of Sci., VI. (1884) p. 437.
ScHNEIDER, E.—Ueber eine Justirvorrichtung an einem Krystallgoniometer.
(On an adjusting arrangement for a Crystal Goniometer.)
[Differential screw. ]
Zeitschr. f. Instrumentenk., TV. (1884) pp. 242-4 (1 fig.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 633
Ster, 8. T.—Das Mikroskop und die mikrographische Technik zum Zwecke
photographischer Darstellung. (The Microscope and Microscopical Technie
in Photographic representation.) Part II. of ‘Das Licht im Dienste
wissenschaftlicher Forschung,’ 2nd ed., pp. i—ix. and 151-822, figs. 168-302,
pls. iili-vi. S8vo, Halle a. 8., 1884.
Srowe.i, C. H.—Rochester meeting [of American Society of Microscopists].
The Microscope, IV, (1884) pp. 131-2.
SrrasBuRGER, E.—Das botanische Practicum. Anleitung zum Selbststudium der
mikroskopischen Botanik fiir Anfanger und Fortgeschrittnen. (Practical
Botany. Guide to the study of microscopical Botany for beginners and
advanced students.) xxxvi. and 664 pp., and 182 figs. 8vo, Jena, 1884.
TatsoT, R.—Das Scioptikon, Vervollkommneter Projectionsapparat fiir den
Unterricht. 7th ed., vi. and 82 pp. 8vo, Berlin, 1884.
[Mainly a Catalogue of Photograms and microscopical preparations. ]
Tuurston, E.—The Microscope : its Construction and Manipulation.
Micr. News, 1V. (1884) pp. 150-2.
Waters, W. H.—Histological Notes for the use of Medical Students. vi. and
65 pp. 8vo, Manchester and London, 1884.
(‘The body-tube of the Microscope is (not aptly) styled the “ telescope-tube ”’ !
and the concave mirror the “ curved mirror.” ]
Wenham Button.
(To keep the Wenham button or the common hemispherical lens in position
while examining temporary mounts, fix it with glycerin or immersion
fluid to that surface of a slide on which has been turned a wax or an
asphalt ring, the internal diameter of which corresponds to the diameter
of the lens. Invert the slide, and it is ready for use.
The Microscope, TV. (1884) p. 134.
8. Collecting, Mounting and Examining Objects, &c.
Methods of Investigating Animal Cells.*—Dr. A. Brass has de-
voted several years of close study to the structure and life of animal
cells, and gives a detailed account of his methods. The following
are some of the more important of these methods :—
1. Protozoa.—As most Protozoa move very rapidly when hungry,
it is well to feed them before attempting to study them with the
Microscope. If well fed with powdered pieces of plants, &c., they
usually remain quiet after a short time, and begin to assimilate the
food-material which they have appropriated. In this condition of
comparative quiet they can be easily examined with high powers.
For this purpose they may be placed under a cover-glass with a
considerable quantity of water and a number of small green alge to
keep the water supplied with oxygen.
For higher powers Abbe’s illuminating apparatus is extremely
useful. In some cases it is desirable to have a completely one-sided
illumination, and this is best effected by inserting beneath the
illuminating apparatus a circular diaphragm-plate perforated with
a slit 2 mm. wide that runs parallel to the edge of the plate. It
is best to leave about 2 mm. between the slit and the edge of the
* Zeitschr. f. Wiss. Mikr., i, (1884) pp. 39-51, Cf, Amer. Natural., xviii.
(1884) pp. 650-1.
Ser. 2,—Vo1. LY. ov
634 SUMMARY OF OURRENT RESEARCHES RELATING TO
plate. Several diaphragm-plates should be prepared in which the
slit varies in extent from a half to a whole of a quadrant or more.
The following mixture, which is Meckel’s fluid with the addition
of a little acetic acid, is recommended above all other reagents as a
preservative medium :
@hromiciacid ois 4 ee) ie ee eee ge eee panty
Platinum ehloridey auc) iscsi alesse ae een
Acetic acid He eS. poh raeion Rah hmhacne MARR a hla pa
Water 94% fn a 400=1000 parts:
Unicellular animals die very slowly in this mixture, and suffer
very much less alteration in structure than when killed in osmie acid
or picro-sulphuric acid.
A special method is required for Protozoa filled with opaque food-
material. In many cases the nucleus and the structure of the cell-
body are completely obscured by foreign bodies. The method
adopted in such cases is as follows :—
(1) Placed in picro-sulphuric acid 3-4 minutes.
(2) Transferred to boiling hot water for a short time.
(3) Placed in water and a little ammonia added; this causes the
contracted object to swell up to its original size and form.
(4) Neutralize the ammonia with a little acetic acid, and then
5) Colour with borax-carmine or ammonia-carmine.
(6) Wash and examine in dilute glycerin.
The picro-sulphuric acid destroys the nutritive material; the
ammonia dissolves any particles of fat that may be present; and thus
the object becomes transparent as far as. possible.
A concentrated solution of corrosive sublimate may also be used
with success for killing Protozoa; but care must be taken to wash
thoroughly.
Dr. Brass has obtained his best results without reagents or dyes.
Born’s Method of Reconstructing Objects from Microscopic
Sections.*—Dr. G. Born describes in detail a very ingenious method
of constructing models of objects from serial sections. By the aid of
the camera the outlines of the sections are transferred to wax plates,
which are then cut out so as to correspond in outlines as well as
dimensions to the sections equally magnified in all three directions.
With plates thus prepared, it is only necessary to put them together
in the proper order to obtain a complete model. The method is
simple and extremely useful, especially in investigating objects with
complex internal cavities. Born has made use of the method in
studying different parts of the vertebrate head; Swirski, in eluci-
dating the development of the shoulder-girdle of the pike; Stohr, in
tracing the development of the skull of Amphibia and Teleostei; and
Uskow, in studying the development of the body-cavity, the
diaphragm, &e.
* Arch. f. Mikr. Anat., xxii. (1883) pp. 584-99. Cf. Science, ii. (1883),p. 802,
and Amer. Natural., xviii. (1884) pp. 446-8. 5
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 635
Born makes use of three rectangular tin boxes of equal sizes, each
measuring 270 mm. x 230 mm. x 24 mm. Sections should be made
about 1/25 mm. thick (never thinner than 1/50 mm.). If we desire
to construct a model of an object from serial sections 1/30 mm. thick,
which shall be magnified 60 diameters, then the wax plates must be
made 60 times as thick as the sections, i.e. 2 mm. thick.
The surface of a plate that could be made in a box of the above-
named dimensions, contains 62,100 sq. mm.; and the volume of such
a plate 2 mm. thick would therefore be 124°2 c.cm. The specific
gravity of common raw beeswax amounts to ‘96-97. For use, it
requires only to be melted ‘and a little turpentine added to make it
more flexible. Thus prepared, its specific gravity is about *95; and
this number has been found sufficiently accurate in all cases. The
weight of the wax required to make one plate of the above size, will
accordingly be 117°99 gr., or, in round numbers, 118 gr. The wax
having been weighed and melted, the tin box is first filled 14 cm.
deep with boiling water, and then the melted wax poured upon the
water. If the water and the wax are quite hot, the wax will gene-
rally spread evenly over the surface; if gaps remain, they can be
filled out by the aid of a glass slide drawn over the wax. As soon as
the plate has stiffened, and while it is still soft, it is well to cut it
free from the walls of the tin box, as further cooling of the water and
the box might cause it to split. By the time the water becomes
tepid, the plate can be removed from the water to some flat support,
and left till completely stiffened. Half a hundred plates may thus be
prepared in the course of a few hours.
The outlines of the section are transferred to the plate in the
following manner: a piece of blue paper is placed on the plate with
the blue side turned towards the wax, and above this is placed a sheet
of ordinary drawing paper. The outlines are drawn on the latter by
the aid of a camera, and at the same time blue outlines are traced on
the wax plate. The plate can then be laid on soft wood and cut out
by the aid of a small knife. Thus a drawing and a model of each
section are prepared. The plates thus prepared can be put together
in the proper order, and fastened by the aid of a hot spatula applied
to the edges.
Shrinking Back of Legs of Oribatide in Mounting.*—A. D.
Michael suggests a mode of getting over the difficulty of the shrinking
back, during the process of mounting, of the legs of species of Oribata
and other genera which have special cavities for the reception of the
legs. The process requires careful manipulation, but if well done is
very successful. Place a very thin layer of balsam upon the slide
upon which the specimen is to be soaked in oil of cloves; when this
layer becomes sticky the specimen is placed upon it, dorsal surface
downwards. The mounter must then extend the legs and stick them
to the balsam, if they rise up they should be pressed down again with
a hair; when they are all fast the body should be brushed over with
the smallest possible quantity of oil of cloves to prevent its drying,
* «British Oribatidw’ (Ray Society) 1884, pp, 104-5.
20
636 SUMMARY OF CURRENT RESEARCHES RELATING TO
but without touching the legs. This brushing with oil of cloves must
be repeated from time to time as it sinks into the body. Whena
creature is ready, which can only be learned by experience, a large
drop of oil of cloves, not benzole, may be put on; when this has
thoroughly dissolved the balsam, but not before, the specimen may be
moved and mounted, or further soaked in oil of cloves.
Preparing the Liver of the Crustacea.*—For the study of fresh
tissues J. Frenzel places a small piece of the organ on the slide, in
the blood of the individual from which it was taken ; or, in sea-water
diluted until the salt contained amounts to about 13-2 per cent. (one
part distilled water and one part sea-water from the Bay of Naples).
The so-called “ physiological salt-solution” (8/4 per cent.) worked
unfavourably, causing maceration.
Various fluids were employed for killing and hardening, partly
for determining the effect of different reagents on the nuclei and
the protoplasm, and partly for finding the best means of preparing
the object for sectioning.
Very good preparations were obtained with warm alcohol from
70-90 per cent.; while direct immersion in absolute aleohol did not
prove advantageous. This treatment gave good results for the cell-
protoplasm, but destroyed the structure of the nuclei, Still better
results were obtained for the cells (not for the nuclei) by adding a
few drops of iodine to 70 per cent. alcohol.
The most satisfactory results were reached by immersing the
object in a saturated aqueous solution of corrosive sublimate from
ten to thirty minutes, then washing with water, and finally replacing
the water gradually with alcohol.
Perenyi’s fluid gave best results when combined with corrosive
sublimate. The object was left from five to ten minutes in the
first-named fluid, then transferred to the second and left for the same
time.
While these methods were good for the Decapods, Amphipods, and
Phronimide, the Isopods required a different treatment. With these,
Kleinenberg’s picro-sulphuric acid, diluted with an equal volume of
water, and allowed to act 15-20 minutes, gave much better preparations
than the sublimate solution.
Preparing Alcyonaria.{—In studying the mesenterial filaments
of the Alcyonaria, E. B. Wilson obtained the best results in the
following manner.
The animals were suddenly killed by momentary immersion in a
mixture of 1 part strong acetic acid and 2 parts of a concentrated
solution of corrosive sublimate in fresh water. After being quickly
washed, they were transferred to a concentrated solution of sublimate
in fresh water and left two or three hours; the internal cavities
being injected with the solution, where this was possible. The
were then thoroughly washed in running sea-water, then in distilled
ees Zool, Stat. Neapel, v. (1884) p. 51. Amer. Natural., xviii. (1884)
pp. 556-7.
+ MT. Zool. Stat. Neapel, v. (1884) p. 3.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 637
water, and finally preserved in successive grades of alcohol. A
weak solution of iodine in alcohol and sea-water also gives beau-
tiful results, but is less certain in its action. For staining he
used Grenacher’s alum-carmine, borax-carmine, picro-carmine, and
Kleinenberg’s hematoxylin. Much the best results are obtained by
the use of alum-carmine, but it must be used as quickly as possible,
since the gelatinous tissue of the mesoderm is apt to shrink if the
object be left too long in aqueous fluid. The tissues were decalcified
with very weak nitric or hydrochloric acid in 90 per cent. alcohol.
For maceration, the Hertwigs’ well-known mixture of osmic and
acetic acid gives good results.
Semper’s Method of making Dried Preparations.*—B. Sharp
redescribes this process.
After hardening in chromic acid solution (4-1 per cent.) and being
repeatedly washed, the object is placed in alcohol, 30-40, 60-70, and
90-95 per cent. successively, and finally in absolute alcohol.
This stage of absolute alcohol is the most critical part of the
whole process. Absolutely every particle of the water must be removed,
and the secret of the whole process depends on this one point. If
any water be left in the tissue, it will become spotted and eventually
spoil. After all the water has been withdrawn by the absolute
alcohol, by remaining in it for three days to a week, the object is
placed in turpentine, the best that can be procured. In this it is
allowed to remain until it becomes thoroughly saturated: with large
objects it is best to change the turpentine once. Two or three days
are required for this stage. When saturated, the object is quite stiff,
and when the process is successful little or no contraction has taken
place. The object is then placed in the air and protected carefully
from the dust, and the turpentine allowed to evaporate. The object
then soon presents a very beautiful appearance; it becomes white,
resembling the whitest kid. It is light, stiff, and, on account of the
resin it contains, is perfectly insect-proof. In annelids the iridescence
is perfectly kept ; hair and feather retain their original colours.
Method of Detecting the Continuity of Protoplasm in Vegetable
Structures.{—W. Gardiner makes the following observations on the
various methods for observing the protoplasmic threads which pass
from cell to cell.
During the earlier part of his work he used sulphuric acid in
combination with Hoffmann’s violet. This latter reagent, at the
time of staining, colours equally protoplasm and cell-wall. If,
however, the section be treated for some time with dilute glycerin,
the staining of the cell-wall is removed, and the protoplasm alone
remains clearly stained. A very useful reagent for the demonstration
of sieve-tubes may be made by dissolving Hoffmann’s violet in strong
sulphuric acid. After treatment with this solution the sieve-tubes
are well brought into view, and all lignified tissue assumes the usual
* Proc. Acad. Nat. Sci. Philad., 1884, pp. 24-7.
+ See this Journal, i. (1881) p. 706.
t Arbeit. Bot. Inst. Wiirzburg, iii. (1884) pp. 53-60 (English).
638 SUMMARY OF CURRENT RESEARCHES RELATING TO
gold-yellow tint, as after treatment with aniline chloride and hydro-
chloric acid.
In working with sulphuric acid the fresh material is first cut
in water. A section having been taken up with a platinum spatula,
-and the excess of water removed by blotting-paper, a drop of strong
sulphuric acid is placed upon it, and allowed to act for a short
time, usually a few seconds. The section is then plunged into water
and rapidly washed. After several washings it may be stained and
mounted. Asa staining reagent, either Hoffmann’s violet or prefer-
ably Hoffmann’s blue may be used. In the former case the section
is quickly stained, washed in water, and then placed for twenty-four
hours or more in dilute glycerin, which dissolves out a great portion
of the dye from the stained cell-wall, and at the same time removes
the peculiar staining of the pits, which, if allowed to remain, is apt
to lead to very delusive results. The section is finally mounted in
glycerin. When Hoffmann’s blue is used, a moderate quantity of
the dye is dissolved in a 50 per cent. solution of alcohol to which
have been added a few drops of acetic acid. After staining, the
sections are washed with water and mounted in glycerin. Or a suffi-
cient quantity of the dye may be dissolved in a 50 per cent. solution
of alcohol which has been saturated with picric acid, until the solution
assumes a dark greenish-blue tint. To this solution Gardiner gives
the name picric-Hoffmann’s-blue. After staining, the sections are
washed with water and mounted in glycerin as before; or, after treat-
ment with alcohol, they may be cleared with oil of cloves and mounted
in Canada balsam.
In Tangl’s method, sections of endosperm were stained with iodine
and mounted in chlor-zinc-iod. In such dry tissue as ripe endo-
sperm cells the cell-walls do not turn blue, but merely remain stained
with the ordinary yellow-brown due to iodine. The protoplasm, on
the other hand, assumes a very dark brown coloration, and after
some time there comes into view a series of strie traversing the
thickened cell-wall, which, from their coloration, and from the
fact that their depth of staining varies pari passu with that of the
protoplasm, are taken to be essentially protoplasmic in character.
Although in cases where it can be applied this method is of great
value, it is attended also with some disadvantages. Firstly, in tissues
containing a higher percentage of water the walls assume the ordinary
cellulose blue, which at once prevents the threads from being seen ;
and, secondly, on account of the extensive and varied staining pro-
perties of the iodine, the results obtained by it alone cannot be taken
as entirely conclusive. But, where practicable, Tangl’s method is
of great use in giving at least an idea of the existence of the proto-
plasmic threads, and the staining of the threads with iodine is much
more distinct than with any other reagent.
To obviate these difficulties Gardiner adopted the modification
already described of dissolving Hoffmann’s blue in a 50 per cent.
solution of alcohol saturated with picric acid ; and, on washing out,
the threads were found to be well stained, the picric acid bodily
carrying, as it were, the solution of the dye into the fine protoplasmic
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 639
strands. Picric acid has also another valuable property in tending to
prevent the staining of cellulose by dyes which, although possessing
an especial affinity for protoplasm, will stain the cell-wall also unless
some such restraining reagent be used. The sections are first stained
with iodine and mounted in chlor-zinc-iod. If the material is
favourable, something may then be seen of the threads. After being
exposed to the action of the chlor-zinc-iod for about 12 hours,
the sections are well washed, stained with picric-Hoffmann’s-blue,
washed again in water, and finally mounted in glycerin, or, better still,
placed in alcohol, first dilute and at length absolute, cleared with oil of
cloves, and mounted in Canada balsam. In those cases where the tissue
swells rapidly under the action of the reagent, as in the endosperm of
Strychnos nux-vomica, Bauhinia, and Tamus, the action need not be so
prolonged, and the excessive swelling must be prevented by the use of
alcoholic iodine at the outset, and in a similar manner it may be
washed with alcohol instead of with water, otherwise the threads will
be so displaced or altered as to be almost or entirely invisible.
As regards the management of the reagents, and the length of time
they must be allowed to act to obtain a satisfactory result, the mani-
pulation must be varied to a certain extent to suit the requirements of
the various kinds of tissue, according as it is thick- or thin-walled,
easily swollen or only with difficulty. The use of sulphuric acid is
attended with a much greater amount of difficulty; for if it is
allowed to act for too short a time, the cell-wall will not be sufficiently
swollen; while if the treatment is prolonged, the middle lamelle of
the walls are liable to swell and at the same time stain, and will
then hinder all successful observation of the threads which may traverse
their substance. Upon still further action the protoplasm itself com-
mences to be attacked. With chlor-zinc-iod, on the other hand,
where the action is much more regulated and gradual, but little pre-
cautionas to length of time need be observed. Besides the difficulty
of regulating its action, there are still other and grave objections to
the use of sulphuric acid. One of these is that, no matter how care-
fully the acid is added to the tissue, and no matter how quickly the
washing in water is accomplished, there will be a very considerable
evolution of heat attending the hydration of the acid, which is liable
to accelerate its action and to cause very grave changes in such delicate
structures as fine protoplasmic threads traversing the cell-wall. The
folding up and general displacement of the tissue consequent upon the
action of such a violent reagent also greatly increases the already
existing complications which attend all observations connected with
minute histology.
For these reasons, while sulphuric acid is a very valuable reagent,
both for swelling up resistent tissues on which chlor-zinc-iod has
but little action, and for demonstrating in an unusually clear way the
remarkable manner in which the apices of the protoplasmic processes,
entering the pits, cling to the pit-closing membrane, it is, on the
whole, the less satisfactory of the two, and the phenomena resulting
from its action can only be rightly interpreted in the light of the
more certain results obtained by the use of chlor-zinc-iod. For all
640 SUMMARY OF CURRENT RESEARCHES RELATING TO
tissues which will swell sufficiently under its action, the chlor-zinc-
iod method may be regarded as perfectly satisfactory; after treat-
ment with picric-Hoffmann’s-blue and subsequent washing with water,
nothing but protoplasmic structures will be stained. In-clear instances
where a thick closing membrane is plainly traversed by threads, it can
be demonstrated with ease that, while the individual threads are well
stained, the substance of the pit-membrane itself undergoes no colora-
tion, even when the section has been exposed to the action of the dye
for a long time. When the pits are smaller and the threads less
clearly defined, it is more difficult to observe that the substance of the
pit-membrane is still free from coloration ; and when, owing to the
thinness of the closing membrane, all appearances even of striation
cease to be recognizable, only an apparent staining of the entire
membrane can be observed. Such staining points, however, in the
opinion of the author, not to the coloration of the substance of the
pit-membrane, but to the staining of protoplasmic threads traversing
its structure.
Besides a platinum lifter, the author uses platinum needles, and is
careful thoroughly to brush all the sections with a camel’s-hair brush,
both after the action of the acid or of chlor-zinc-iod and after
staining.
To prove that the threads traversing the cell-wall are actually pro-
toplasm, he employed with success a solution of molybdic acid in strong
sulphuric acid, which has the advantage of swelling the cell-wall and
at the same time colouring the protoplasm. The solution is colourless
and gives a beautiful blue colour with alcohol and many other organic
substances; and this reaction is extremely delicate. While not
affecting the cell-wall for some time this reagent gives at once a fine
blue coloration with protoplasm. If a section of some living endo-
sperm, such as that of Tamus, is treated with it, the cell-wall will
swell up, and it will commence to dissolve the protoplasm ; the fine
threads perforating the walls will remain for some time unaffected,
but will soon be perceptibly coloured, while the main mass of proto-
plasm will assume an intense blue.
The pit-membrane itself possesses some properties different from
those of the cell-wall. After staining with iodine and chlor-zinc-
iod, while the cell-wall assumes the usual blue tint, the pit-mem-
brane is but slightly coloured, and, when thin, appears as if not coloured
at all, although the examination of a fine transverse section of the pit
will prove that a definite staining has taken place. But the depth of
the staining is less than might have been expected in proportion to the
thickness of the membrane. Methylene blue stains both the wall and
the pit-membranes a fine light blue, and, after the action of sulphuric
acid, the swollen wall assumes a much lighter tint, owing to the fact
that the quantity of the dye taken up by the cell-wall is now distri-
buted over a larger space. If a section is cautiously treated with
sulphuric acid, washed, and stained, it will be seen that, whereas the
general swollen wall is coloured a light blue, the bottoms and the sides
of the pit retain the darker blue colour of the unswollen cell-wall, and
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 641
will thus be clearly marked out. If, however, another section is
treated for a longer time with acid, or the same section is a second
time exposed to its action, no special coloration of the bottoms and
sides of the pits takes place on staining, but the whole swollen wall is
of a uniform light tint. This shows that the substance of the pit-
closing membrane and of the layers immediately surrounding the pit-
cavity are more resistent than the rest of the cell-wall; as indeed has
already been pointed out by Strasburger.
Exactly the same phenomena are observed when a section, after
cautious treatment with sulphuric acid, is stained with methyl-violet.
In the case of methylene blue the protoplasm is not coloured, but
when methyl-violet is used, a deep staining of that structure occurs,
the tint of which is the same as that of the bottoms and sides of the
pits; for, while the general cell-wall assumes a violet colour, the pro-
toplasm, the pit-membranes and the sides of the pits appear of a deep
purple. Now since protoplasmic processes from the main protoplasmic
mass may project for some distance into the swollen pits, when such a
stained section of pitted tissue is examined, it appears as if there were,
in any two contiguous cells, threads of protoplasm of a purple colour
traversing the thickness of the violet cell-wall by means of the pits,
and thus establishing a direct continuity of the protoplasm from cell
to cell. But after prolonged treatment with dilute glycerin, this
purple colour dissolves from the pits, and the protoplasmic processes
are left clearly seen, and may or may not be the means of establishing
a continuity between the cells. As in the case of methylene blue, so
also here, a more lengthy treatment of the tissue with acid will swell
up the pit-membranes, and when in that condition the pits will assume
the same colour as the rest of the cell-wall.
Method of Preparing Dry Microscopic Plants for the Micro-
scope.*—G. Lagerheim has found the following method convenient
for the examination of alge or other plants which have already been
dried.
A fluid is prepared of the following composition :—1 part fused
potassium hydrate is dissolved in 5 parts water, and when the solu-
tion is complete 5-5 parts are added of glycerin of the consistency of a
syrup. The dried desmids, Cidogoniacee or other alge, are treated
with water till they are thoroughly moist; a small piece of the
material is then taken up with a pincette and placed upon the glass
slide. One or two drops of the fluid are added, and the alge
distributed as evenly as possible with dissecting-needles. The glass
slide is then warmed for a time over a spirit-lamp, and a cover-glass
finally placed on. The potassium hydrate has now caused the
previously shrunken alge to swell and resume their original form.
The addition of glycerin gives a consistency to the fluid, so that the
alge can easily be turned over by shifting the cover-glass, and thus
observed on different sides, a point of great importance, for example,
in the study of desmids.
* Bot. Centralbl., xviii. (1884) pp. 183-4.
642 SUMMARY OF CURRENT RESEARCHES RELATING TO
The alge prepared in this way can readily be drawn or measured.
The cover-glass is carefully removed, and, if a low power or a dis-
secting Microscope is used, the object is taken up by a needle or stiff
bristle, and again at once placed in potassium acetate or glycerin.
Tf, on the contrary, the whole material thus prepared has to be got
ready for drawing or measuring, a drop of acetic acid is added after
removing the cover-glass. The alge are in this way imbedded in
potassium acetate and glycerin, fluids perhaps the best adapted of
any for the preservation of alge.
Dry mosses and fungi may also be prepared in the same way.
Chapman’s Microtome.*—A. B. Chapman has devised a micro-
tome, which has for its cutting surface two parallel glass-plates
cemented to a block of mahogany, through which is inserted a brass
cylinder at right-angles to the glass plates; in this cylinder (which
forms the “ well” of the microtome) an accurately fitted brass plug
works, carrying on its top a flat-headed table-like piece which entirely
prevents the imbedding agent from rising or turning round while the
sections are being cut. The plug is moved up and down by a brass
disk, which revolves between the block of mahogany and a similar
block underneath. The brass disk is graduated on the edge of its
upper surface, each graduation representing a movement of -0005 in.
of the plug. The microtome has a base-board which can be firmly
clamped to a table, and the whole is so conveniently arranged that
every operation or adjustment can be made at once, the whole being
in view on the table.
Use of the Freezing Microtome.t—The tendency at the present
time is to make all microscopic sections by the dry method after paraffin
infiltration and imbedding; but no doubt there is a ‘place, and an
important one, for the freezing microtome in practical histology, and
in this note 8. H. Gage calls attention to what seem to him improve-
ments in its use.
Disliking greatly the disagreeable mess made by ice and
salt, it occurred to him to take advantage of the device of plumbers
to thaw out water and gas pipes,—to use strong alcohol with
the ice or snow instead of salt. By using snow or finely powdered
ice and 95 per cent. alcohol, a temperature of 20 C. below zero is
obtained within five minutes, and this temperature may be maintained
with far less trouble than with ice and salt. The microtome used is
the Rutherford pattern, modified by placing the drain near the top
instead of in the bottom. A rubber tube passing from this drain to
a jar preserves the overflow. It requires about 250 c.cm. of
alcohol to freeze and keep frozen one tissue for cutting, but this is
not lost, as little evaporation takes place, and the dilution does no
harm for many purposes, hence the method is not wasteful, while it is
much more pleasant and expeditious than with salt.
Ordinarily tissues are infiltrated with thick gum before freezing,
* Sci.-Gossip, 1884, p. 137.
+ Science Record, ii. (1884) pp. 134-5.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 643
and then the sections are soaked in a relatively large amount of water
to remove the gum. Evidently while soaking, staining, and trans-
ferring the sections, especially if they be of such an organ as the
lungs, there is every liability of their becoming folded or torn. This
may be avoided by staining the tissue in the mass as for dry
section-cutting, and then soaking in water to remove any alcohol, and
finally completely infiltrating the tissue in a thick solution of very
clean gum arabic.
When ready to make the sections the well of the microtome is
filled with the thick gum and the tissue introduced at the proper
time as usual. Before cutting, the gum is cut away from the tissue
as in sharpening very bluntly a lead pencil, then as the sections are
cut they are transferred directly to the slide. After several slides are
filled, a drop of glycerin is added to each section and the cover-glass
applied. This is practically mounting in Farrant’s solution.
Apparatus for Injection—Fearnley’s Constant-Pressure Apparatus.
—Very great variety exists in the forms of this class of apparatus. In
the majority of them the leading principle is the compression of the
air in an intermediate vessel by the entrance into it of a liquid falling
from a greater or less height according to the pressure required, the
air then acting on the injecting fluid in another bottle communicating
with the first.
In the two following the intermediate vessel is dispensed with.
Ranvier’s * (fig. 108) has a syringe connected by an indiarubber tube
Fia. 108.
with the bottle containing the injecting fluid, which is supported on
a retort-stand. A second indiarubber tube terminates in the canula,
Ludwig's t (fig. 109) acts by the fall of quicksilver drop by drop into
the vessel, A, containing the injecting fluid I.
* Thanhoffer’s ‘Das Mikroskop und seine Anwendung,’ 1880, p. 187 (1 fig.).
+ Ibid., p. 188 (1 fig.).
644 SUMMARY OF CURRENT RESEARCHES RELATING TO
Toldt’s * (fig. 110) is similar to the preceding, but in addition to
the vessel containing the injecting fluid, a second air-vessel is
introduced.
Thanhoffer’s.t Prof. L. v. Thanhoffer uses the following apparatus
(fig. 111). To the wall of the room and near the ceiling a board is
fixed. This board carries a pulley, over which a cord is passed, having
at one end a large glass vessel A, filled with water ; at the other end of
the cord is a handle, by which the vessel can be drawn up and down
as required. When the tap in Ais open, water flows through the india-
Fie. 109. Fig. 110.
=
eS
Vf
|
rubber tube into a second vessel B, which acts as an air-reservoir.
The air compressed in B passes into C, which contains the injecting
fluid, and forces it through the discharge pipes and thence into the
vessels. The pressure is of course increased according as A is raised.
The amount of pressure is denoted by the manometer M. Quicksilver
may be substituted for water, and greater pressure thereby obtained,
. Thanhoffer’s ‘Das Mikroskop und seine Anwendung,’ 1880, p. 189
(1 fig.).
+ Ibid., pp. 190-2 (1 fig.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 645
but in injecting fine vessels this is quite unnecessary, for if the room
be sufficiently lofty a pressure of from 300 to 400 mm. can be obtained
Hie. 111,
SS
CATALAN TD
PUTY ODIO UV ULUOUUUIUVNDUNE UNNI
VTE TT
ITA
by drawing the vessel A to the ceiling, a pressure which is more than
is required.
646 SUMMARY OF CURRENT RESEARCHES RELATING TO
Ludwig's * (fig. 112) for quicksilver and small pressure, is substan-
tially identical, and requires no explanation beyond the figure.
Fig. 112.
SSS aaa
TRDDIT CAN OUTDATED
* Thanhoffer’s ‘Das Mikroskop und seine Anwendung,’ 1880, pp. 192-3 (1 fig.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 647
Ranvier’s * (fig. 113) consists of a glass vessel filled with quicksilver
which can be raised and lowered on a retort-stand. The rise of the
quicksilver in the intermediate vessel compresses the air which it
contains as well as that in the bottle containing the injecting fluid,
which is forced out as in the previous case. In another form (fig. 114)
Fig. 114.
the pressure is obtained by compression of an indiarubber ball K
communicating with an air-reservoir R (M being a manometer).
Hering’s + (fig. 115) consists essentially of two glass bulbs, A A’,
having a thin glass tube pass-
ing through the stoppers in Fia. 115,
their necks, and by which the
bulbs communicate with each
other. A flexible tube from
each bulb passes into one or
other of the bottles E E, con-
taining the injecting fluid.
The ends of the glass tubes
are drawn out so fine that the
quicksilver passes only a drop
at a time from one to the other
(even when the air is com-
pressed). When the bulbs are =
turned on their axis, and in- & IOCOUTY OOO TOONS VON T OOOO CTD OOOO OC OTTO
stead of the horizontal posi-
tion I., take the oblique one II., the quicksilver will flow from A to
A’, and compress the air in the bulb A’, and act upon the injecting
fluid in the vessel E. The nearer a vertical position is approached,
the greater the pressure will be by which the injecting fluid is forced
into the blood-vessels. The two bottles, E and E, are alternately
used according as one or the other of the bulbs is uppermost.
* Thanhoffer’s ‘Das Mikroekop und seine Anwendung,’ 1880, pp. 189-90,
187-8 ¢ figs.)..
+ Ibid., pp. 193-4 (1 fig.).
t The figure, which is a cliché of the original, should have indicated one of
the two positions of the bulbs by dotted lines. As drawn, there appear to be four
bulbs. B, ©, and D are not explained but their function is obvious,
648 SUMMARY OF CURRENT RESEARCHES RELATING TO
Other forms are described by Dr. P. Latteux in his ‘Manuel de
Technique Microscopique.’
Da ee * (fig. 116) consists of a copper globe B, to hold the
compressed air, having a tube at A with mercury serving as a mano-
meter. Four taps are inserted in the globe of which one is the air
iniges, TWIG,
FSS) Fee Bt Eat et SS
tube from the indiarubber ball C, another regulates the pressure,
and the third and fourth H E communicate with two bottles F F
containing carmine and blue, the exit tubes G H from these bottles
terminating in canul for insertion in a vein and artery, or artery and
gland duct.
= o utae P., ‘Manuel de technique microscopique,’ 2nd ed., 1883, pp. 110-12
g.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 649
The apparatus is sufficient to completely fill the finest vessels of
the retina, spinal cord, &c.
Fearnley’s Constant-Pressure Apparatus.*—The method of Ludwig
has always been acknowledged as superior to injecting by the syringe
except for the one great obstacle—applying the necessary pressure,
which had to be effected by elevating and depressing huge water-
Fig. 117.
bottles or by connecting the air-pressure bottle with a water-tap and
regulating the pressure as best one could, thus rendering the pressure
almost as uncertain and irregular as the thumb-pressure of the
syringe. Mr. W. Fearnley’s method is to apply the pressure with an
ordinary Higginson’s enema syringe (figs. 117 and 118).
No practice is required with this simple contrivance beyond
introducing and tying in the nozzle in the aorta.
* Brit. Med. Journ., 1883, pp. 859-60 (2 figs.).
Ser. 2.—Vou. IV. 2x
650 SUMMARY OF CURRENT RESEARCHES RELATING TO
There is a bath, having a shallow part for the animal to lie in,
and a deeper part for the Woulff’s bottle, containing the injection-
mass, to stand in. A large (40 ounce) Woulff’s bottle, with three
necks, is fitted with three perforated indiarubber stoppers. ‘The
middle stopper is perforated with a glass tube which goes to the
bottom of the bottle. Each of the others is perforated with a glass
tube, the depth of the stopper only, and standing above the stopper
sufficiently to admit of a piece of indiarubber tubing being fixed
upon it. The Woultf’s bottle containing the mass has two necks,
fitted with indiarubber stoppers. One neck admits a piece of glass
tube, which goes quite to the bottom of the bottle; the other admits
a short piece of tube the depth of the stopper only. Fig. 117 shows
all further detail.
The mercurial manometer allows five inches rise of the mercury
in the ascending arm—therefore five inches fall of the descending arm
—though four inches will do.
“To inject an animal, a rabbit, for instance, proceed as follows :—
Fill the bath with water, and heat the water with a Bunsen’s burner
to 100° Fahr. or so. The Woulff’s bottle containing the mass should
be filled and thoroughly stoppered. Then chloroform the rabbit and
make an L-shaped incision into the thorax, so as to expose the heart
and aorta. This is done by cutting up the middle line of the sternum
(breast-bone) as far as the root of the neck nearly, then making a second
incision at right angles to this to the rabbit’s left. A triangular flap
is thus made, and the heart inclosed in the pericardium exposed.
Having cut through the pericardium, seize the apex of the heart with
a pair of forceps and snip it off, then the heart’s apex appears as in
A, fig. 118. That is to say, the right and left ventricles are opened,
and the animal instantly bleeds to death. Mr. Fearnley uses a nozzle,
as in B, Fig. 118, which has an elastic collar ec, which is plugged by
a nozzle, as here shown.
The opening in the right ventricle leading to the pulmonary
artery has a crescent shape or slit-like appearance; whilst the opening
in the left ventricle, leading to the aorta, is round, Therefore, if we
wish to inject the entire arterial system, we insert our nozzle into
the round hole; but if we wish to inject the pulmonary system only,
we choose the crescentic slit.
Hither glass nozzles,* or those shown in fig. 118, are to be inserted
into one or other of the two holes (usually the round one for injecting
the entire arterial system with carmine and gelatine mass). We can
now either tie the artery only, or we can tie the whole heart substance.
In either case a ligature of floss silk is to be passed round (the artery
or the entire heart) and tightly tied and secured. Before proceeding
further, we wash out the cavity of the thorax of all blood to keep our
bath water clean, then we lift the animal into the bath and there let
it remain ten minutes or so to get well warmed. It is a good plan
to slit open the entire abdomen in the middle line, so as to allow the
* Mr. Fearnley informs us that he now uses glass nozzles with tube connec-
tions, which answer quite as well as those figured, and are cheaper.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 651
warm water to freely get round the abdominal contents: the mass
thus gets into every organ and into every part of an organ evenly.
We now connect the pressure bottle with the manometer and with
the Higginson’s syringe, as shown in fig. 117, also with the mass
bottle. The tube of the mass bottle, which is to convey the mass
away from the bottle, is now clamped, as shown at O, fig. 118, and
must never for an instant be allowed to get out of the warm water
into the cold air.
Fic. 118.
Having our small basin full of water, we now squeeze the Higgin-
son’s syringe, watching the manometer, to raise the mercury half an
inch. This done, we remove the clamp from the efflux tube, and the
red fluid after driving out a few air-bubbles begins to flow out; we
at once make the connection, and all quicksands are passed if we have
tied in our nozzles properly into the artery and the connecting part,
and fastened in our stoppers thoroughly into our Woulft’s bottles.
Our task is easy now: all we do is to seize the head of the animal,
which should be to our left, with our left hand, to watch the pale
gums, tongue, and eyelids become suffused with a pale blush which
gradually deepens, whilst we gently squeeze and relax the barrel of
the syringe and glance at the mercury from time to time. When the
mercury has risen four, or at most five inches, the whole animal will
be completely injected: the visible mucous membranes and bowels
will be dark-red and much swollen.
We now remove the animal, and place it in ice-cold water under
@ common water-tap for an hour or two, and divide it into parts as
required. This method of applying pressure is wonderfully delicate ;
thus, whilst we can raise the mercury in the manometer almost imper-
ceptibly, one entire compression of the barrel raises the mereury
one inch.”
ana
652 SUMMARY OF CURRENT RESEARCHES RELATING TO
Myrtillus for Staining Animal and Vegetable Tissues.*— Dr. M.
Lavdowsky (in furtherance of the modern fashion of recommending
every conceivable substance which by any chance will furnish a
stain) recommends the berries of Vaccinum myrtillus, as an excellent
staining agent for the nuclei of all cells and the cellulose walls of
plant-cells. The karyokinetic figures are shown very plainly...
The fresh berries should be well washed in water, the juice
squeezed out and mixed with two volumes of distilled water, to
which some alcohol (90 per cent.) has been added. It is then heated
for a short time, and filtered warm. For use, a small quantity of
the fluid should be diluted with two or three times its bulk of dis-
tilled water.
The stain gives a red (carmine) colour with fresh neutral objects,
or lilac (hematoxylin) when the acid of the fluid is neutralized by
an alkali or neutral salt. The latter is the more durable. A double
stain is obtained by placing the object in a solution of eosin after
treatment with the lilac stain. Directions are given for applying the
fluid, but it does not appear to us, from the author’s own showing,
to be a valuable or even useful addition to the already long list of
staining agents.
Hartzell’s Method of Staining Bacillus tuberculosis.t—A small
quantity of sputum is spread as thinly and evenly as possible upon a
slide, and allowed to dry, and is then passed slowly several times
through the flame of an alcohol lamp or Bunsen burner. One or two
drops of the fuchsin solution recommended by Gradle (prepared as
follows: carbolic acid 15 minims, distilled water 1/2 fluid oz.,
dissolve, and add saturated alcoholic solution of fuchsin 1/2 fluid dr.)
are placed upon the sputum, and allowed to remain from three to five
minutes. The slide is now washed thoroughly with distilled water,
to remove the excess of fuchsin, and the stained sputum completely
decolorized by a saturated solution of oxalic acid. It is again
thoroughly washed in distilled water, and allowed to dry; it is now
ready to be mounted in glycerin or balsam for examination. With a
power of 500 or 600 the bacilli will appear as brilliant red rods, no
staining of the background being necessary.
One chief advantage claimed over other methods is that in the
latter the decolorizing agent employed is dilute nitric acid ; but this,
besides being disagreeable to handle because of its corrosive and
staining properties, is apt to remove the colour from the bacilli too,
unless great care is taken. Oxalic acid, however, seems to leave the
dye untouched in them.
Safranin Staining for Pathological Specimens,t—For staining
tumours, Dr. V. Babes(in) recommends that fine sections of tissue
hardened in alcohol or chromic acid should be steeped either in a
solution of safranin which has been dissolved in warm water, or in a
mixture of equal parts of concentrated watery and concentrated
* Arch. f. Mikr. Anat., xxiii. (1884) pp. 506-8.
+ Amer. Mon. Micr. Journ., v. (1884) pp. 76-7, from ‘ Medical Times.’
{ Arch. f. Mikr, Anat., xxii, (1883) pp. 356-65.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 653
alcoholic safranin solution for half an hour; they should be washed
slightly in water, and then dehydrated as quickly as possible by
absolute alcohol, then transferred to turpentine and mounted in
balsam. Some tissues which are not so readily decolorized may be
clarified with oil of cloves. Although they appear scarcely red, yet
such sections show the following structures: viz. nucleoli of white
blood-corpuscles; granules in the same and in most cells of rapidly
proliferating granulating tissues; periphery of red blood-corpuscles ;
filamentous bodies occurring in connection with blood-vessels in
process of formation; nuclei of giant-cells and nucleoli of all large-
celled sarcomata and carcinomatous tumours.
As the inactive, skeletal part of the nucleus is not stained by the
safranin, it is easy to follow by its means the part which the nucleolus
plays in cell-division. In large-celled, malignant tumours a great
variety of forms are thus brought out in the nucleus, while the
spindles and the fibrils connecting them remain uncoloured. In
melanosarcoma the fission-stages of the cells, which remain concealed
under every other treatment, are well brought out, and in rapidly
growing small-celled tumours, e. g. lymphosarcomata, the appearance
of universal staining is imparted to the cell by a series of delicate
nuclear markings which almost fill the cell.
Secondly, for investigating the structure of the cell and of other
histological elements a super-saturated solution should be employed ;
it is warmed to 60°, and filtered in this state; the sections are placed
in a small quantity of the liquid in a watch-glass, which is then
warmed * for a few seconds over a spirit-lamp until the precipitating
crystals are redissolved; the sections are left for a minute, then
washed in water, and treated as in the former case. Tissues which
do not stain readily should be warmed again and again. The nuclear
netsork comes out well under this treatment. It is especially
adapted for delicate structures and for bacteria; every micrococcus
appears brownish-red, while the surrounding tissues assume a fine
rose-red ; the bacilli of tuberculosis and lepra are not thus stained.
Thirdly, the sections may be left for 12 to 24 hours in the solu-
tion (either concentrated watery or alcoholic, or a mixture of the two).
Sections thus coloured may be left, if necessary, somewhat longer in
alcohol, turpentine, oil of cloves, or, better, origanum ; a large number
of details are thus brought out, and a similar effect is produced by
longer action of a watery solution; the method is especially adapted
to tumours of the brain or spinal cord.
The finest representations of the changes undergone by nuclei in
fission were produced by rapidly staining with safranin, followed by
eosin, and mounting in balsam. Safranin and hematoxylin bring
out the nuclear skeleton violet and the nucleolus red. Preparations
made according to these methods have proved durable. Some points
are better seen by mounting in glycerin, but the colour disappears
more or less in time, and acetate of potash is preferable both on the
grounds of permanency and clearness.
* Of. this Journal, iii, (1883) p. 918.
654 SUMMARY OF CURRENT RESEARCHES RELATING TO
Preparations which show only the muscular fibre and the elastic
tissue may be made by staining small fragments with a mixture, half
and half each, of oil of cloves or origanum and concentrated alco-
holic solution of safranin and placing for an hour under the air-
pump: sections may then be made at once, or, better, uncoloured
sections may be transferred from alcohol to the oily solution; the
sections are washed with solutions of caustic potash in alcohol, and
mounted in acetate of potash. By putting sections stained with
safranin into 30 to 40 per cent. solution of caustic potash the colour
is fixed, and the elements come out very distinctly ; they should be
mounted in acetate of potash.
Collodion as a Fixative for Sections.*—Sections fixed by means of
a solution of collodion in clove oil, as suggested by Schallibaum,yt
may be coloured on the slide. S. H. Gage, who had begun to experi-
ment with collodion before Schallibaum’s method was published,
recommends that the collodion and clove oil be applied separately.
«A solution of collodion is prepared by adding to 2 gr. of gun-
cotton (that used by photographers is good) 54 ce. of sulphuric ether
and 18 ce. of 95 per cent. alcohol. After the gun-cotton is entirely
dissolved the solution should be filtered through filter-paper or
absorbent cotton. The slides are coated by pouring the collodion on
one end, allowing it to flow quickly over the slide, and off the other
end into the bottle. The prepared slides should be kept free from
dust. As the collodion will not deteriorate after drying on the slide,
any number of slides may be prepared at the same time. Before
using a slide it should be dusted with a camel’s-hair brush, and with
another brush the collodionized surface of the slide should be thinly
painted with clove oil. . . . . The sections are arranged as in
the shellac method. The slide is warmed over an alcohol lamp, and
then heated in a warm chamber, so as to drive off the clove oil. After
cooling, it may be placed in a wide-mouthed vial of turpentine,
chloroform, xylol, or refined naphtha, to remove the paraffin.
Naphtha is very cheap, and is the best agent we have yet tried for
dissolving the imbedding mass. The sections are usually freed from
imbedding mass within half an hour, though the slide may remain in
any of the solvents mentioned for two or three days, or perhaps
indefinitely, without loosening the sections. When the slide is
removed from the naphtha, the sections are washed with 95 per cent.
alcohol by means of a medicine dropper, or by immersing the slide
in alcohol. If the sections are to be stained in Kleinenberg’s hema-
toxylin, or in any other stain containing 50 per cent. or more alcohol,
the slide is transferred directly from the aleohol used for rinsing to
the staining agent; otherwise it should be first transferred to 50 per
cent. alcohol, and from that to the staining agent. Whenever the
sections are sufficiently stained, they may be mounted in any desired
mounting medium. In case Canada balsam is to be used, the slide
must be immersed in alcohol to wash away the stain, and finally in
* Medical Student (N. Y.), i. (1883) pp. 14-6.
t See this Journal, iii. (1883) p. 736.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 655
95 per cent. alcohol to completely anhydrate the sections. They are
cleared with a mixture of carbolic acid 1 part, turpentine 4 parts.
The balsam to be used is prepared by mixing 25 gr. of pure Canada
balsam with 2 cc. of chloroform and 2 ce. of olive oil. The latter
very soon removes any cloudiness that may have appeared in the
collodion film.”
Piffard’s Slides.—Mr. B. Piffard has patented a slide which is
made by forming with a diamond a round recess in an ordinary
slide. In this the object is placed, and covered with thin glass. The
upper surface of the slide is thus perfectly smooth, the cover-glass
being even with the slide. There is no danger of the cover-glass
and object being knocked off; and the recess causes a very beautiful
diffusion of light.
Mounting in Balsam in Cells.*—R. P. H. Durkee describes the
following process :—A curtain-ring, flattened by pressure, is placed
upon a clean slide and the slide placed on the hot table. Drop in
the centre a small portion of balsam, enough to fill the cell, and heat
till the air-bubbles rise and permit of breaking with the needle; at
the same time gently moving the ring about, and pressing it down to
insure contact with the slide. Place the object in the balsam,
taking care to see that it is completely covered ; warm the cover and
place it in position, in doing so holding it in the forceps parallel
with the surface of the slide, so as to expel the air all round. Weight
down with a bullet, and apply heat as may be necessary to harden
the balsam.
What the author considers a feature is that there would seem to
be no possibility of varnish running in, the channel in the top of the
ring receiving the excess of balsam when pressed out by the cover,
and thus forming a barrier to the influx of the varnish used in ring-
ing. For flattening the rings he used two plates of brass, 24 in.
square by 1/8 in. thick. Place the rings, six or more at a time,
between the plates, and press in a lever stamp. This method of
mounting seems to him to have the following desirable features, viz.
no previous preparation and drying of cells, rapidity and neatness of
finish, and no running in of varnish.
Styrax, Liquidambar, Smith’s and van Heurck’s Media. —Dr.
H. yan Heurck writes that styrax, when prepared by exposing the raw
product to the air and light, dissolving and filtering, is no longer of
a dark colour, and that its index is higher than 1°585, as given on
p. 475. The purified styrax of commerce is always darker and of
lower refractive index. Preparations become completely colourless
at the end of a few months, especially if brought into the light occa-
sionally, and the index rises a little.
Liquidambar can be obtained of Lamman and Kemp, William
and Cedar Streets, New York. It must be heated to reduce its
brittleness, and dissolved by means of the water-bath in a mixture of
* Amer. Mon. Mier. Journ., v. (1884) pp. 84-5.
656 SUMMARY OF CURRENT RESEARCHES RELATING TO
alcohol and benzine, and filtered. This is also the best solvent for
styrax.
; Styrax and liquidambar, purified and prepared according to Dr.
van Heurck’s directions, can be obtained of Messrs. Rousseau, 42-
44, Rue des Ecoles, Paris.
Prof. Smith’s medium, while most excellent for difficult diatoms
of delicate structure, is not better than styrax for ordinary diatoms
and preparations of histology or of insects.
Dr. van Heurck also announces that he has discovered a colour-
less medium analogous to that of Prof. Smith, but with an index
higher than liquidambar.
Grouping Diatoms.*—J. Deby calls attention to some slides pre-
pared for him by Moller, each containing many species of the same
genus arranged in several lines. Thus there are 72 species or varie-
ties of Triceratium, 60 of Nitzschia, 45 of Surirella, 38 of Epithemia,
&c. Such slides have, Mr. Deby considers, enormous advantages
over the “type-plates” from the point of view of the comparative
study of the species of a genus. Equally to be recommended, from
a scientific point of view, is, he thinks, the plan by which as many
species as possible from the same gathering are united in one slide.
Quantitative Analysis of Minute Aerial Organisms.t—In the
reports of the Imperial German Board of Health is a paper on this
subject by Dr. Hesse. He employed an apparatus, which in all essen-
tials so corresponds with the portable aéroscope of Dr. Maddox
described in this Journal, III. (1883) p. 388, that it is necessary to
note the fact, as no reference is made to it by Dr. Hesse. Instead,
however, of drawing the air direct into an aéroscope and on to a thin
cover-glass smeared with a glutinous substance for examination of
the deposited matter by the Microscope, a long tube lined with a
layer of gelatine is used. The air is allowed to enter by an aperture
at one end, that most suitable being of like diameter with that of
the exit tube, and as it traverses the tube slowly it deposits the
organisms in its passage.
According to the nature of the deposits, small colonies are deve-
loped in the gelatine at different parts of the tube. By employing a
long tube and slow traverse of air, the bacteria are deposited before
reaching the exit, while the fungi—mildew and spores—appeared more
abundant at the exit end than at the entrance. That bacteria are
rapidly deposited in tranquil spaces was long since shown by Professor
Tyndall.
Microscopical Evidence of the Antiquity of Articles of Stone.{
—An action has recently been pending in New York as to the genuine-
ness of the collection of antiquities brought from Cyprus by Count Di
Cesnola and sold to the city.
Mr. B. Braman, President of the New York Microscopical Society,
* Journ. de Microgy., viii. (1884) pp. 230-1.
+ MT. aus dem K. Gesundheitsamte, ii. Berlin, 188+.
a t ae Mon. Micr. Journ., y. (1884) pp. 14-5, from New York Times, 22nd
ec., .
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 657
was examined as a witness and detailed the result of his examination
with the Microscope of the surfaces of the statues in the collection.
“The Cypriote stone whereof these statues are sculptured is a
cellular calcareous tufa. The cells are minute and crowded. There
are about 1500 to the square inch. They are spherical in shape, and
about 1/100 in. in diameter. When freshly cut, it will be
found that the walls of some cells are harder than the walls of others.
The hard walls resist the effects of the atmosphere with more success
than the softer ones. During exposure these soft spaces sink first,
and leave the hard ones standing, like craters on the face of the moon.
The soft spaces sink into dome-like shapes, and small orifices indicate
that the atmosphere has begun to affect them. Then the cups thus
formed are carried away, the hard projections roll off in small globes,
and the process recommences. Hach process occupies several centuries.
In the case of buried objects in Cyprus, the water filtering through the
ground makes a deposit on them, more or less thick, of carbonate of
lime. I have given seven or eight hours to the microscopical
examination of the statuette of Venus, and it is susceptible of
scientific demonstration that the surface of the so-called mirror and
the surrounding surface are ancient. On the mirror are eight stipples
of carbonate of lime, deposited in the way I have stated, which are an
integral part of the ancient surface, and would not appear on a freshly
cut surface. These evidences of antiquity could not be taken away
without breaking the stone. They fill the cavities whereof I have
spoken. They appear on the surface of the drapery within 3/16 in. of
the mirror’s outline. My Microscope would have disclosed cement
1/1000 in. in thickness.”
“ B.Se.”—Carbolic Acid and Cement.
{Fresh-water Algze mounted three years ago in a weak carbolic-acid solu-
tion with asphaltum for the cement are still perfectly good.]
Sci.- Gossip, 1884, p. 137.
Brant, T. J.—Notes on putting up Microscopic Objects.
Rep. South Lond, Mier, and Nat, Hist, Club, 1884, p. 13.
Chapman’s (A. B.) New Microtome.
[Supra, p. 642.] Sci.-Gossip, 1884, p. 137.
Coxe, A. C.—Methods of Microscopical Research.
Part XI. Mounting (continued). pp. lvii—lxi. (Mounting the Diatomacee.
Cleaning and Mounting Polycystina. Preparation and Mounting of
Insects. Preparation of Vegetable Sections, To Double Stain Vegetable
Sections.)
Part XII. pp. Ixiii-lxxii. On Microscopical Drawing and Painting (by
Ber D:)-
es Popular Microscopical Studies. IX. pp, 39-42, The Crane Fly
(Tipula Oleracea). Plate 9 x 40.
No. X. pp. 43-6. Sponge. Plate 10.
No. XI. pp. 47-52. Starch. Plate 11 (Sarsaparilla officinalis x 400).
me Studies in Microscopical Science.
Vol. Il, No. 19. Sec. I. No. 10. pp.37-40. Nerve of Horse. Plate 10,
at, oe LO.
No. 20. Sec. II. No. 10. pp. 39-42. Vascular Tissue (continued). Plate 10,
Wood Vessels and Cells.
Vol. II. No. 21. Sec. I. No. 11. pp. 41-4. Human Cerebellum, Plate
11, 7.8.5. 150:
No. 22. Sec. II. No. 11. pp. 43-6. Fundamental Tissue. Plate 11.
T.S. Petiole of Limnanthemum x 75.
658 SUMMARY OF CURRENT RESEARCHES RELATING TO
D., E. T.—See Cole, A. C.
Decker, F.—Hin neuer Schnittstrecker. (A new section-smoother.) [ Post.]
Arch. f. Mikr. Anat., XXIII. (1884) pp. 537-43 (2 figs.).
Francorte, P.—Description des différentes méthodes employées pour ranger les
coupes et les diatomées en séries sur le porte-objet. (Description of the
different methods adopted for mounting sections and diatoms in series on
the slide.) Continued. Bull, Soc. Belg. Micr., X. (1884) pp. 137-41.
e se Petit instrument qui permet de repasser sur le cuir les grands
racoirs du Microtome de Thoma. (Small apparatus for sharpening on the
strop the large razors of Thoma’s Microtome.) [Post.]
Bull. Soc. Belg. Micr., X. (1884) pp. 151-2.
FRIEDLANDER, C.—Microscopische Technik zum Gebrauch bei medicinischen und
pathologisch - anatomischen Untersuchungen. (Microscopical Technic in
medical and pathological-anatomical researches.) viii. and 123 pp. and 1 pl.
Qnd ed. 8svo, Berlin, 1884.
Grirrin, A. W.—On the Collection and Preparation of the Diatomacexe. Part I.
Collection.
(“An attempt to gather together some of the ideas of the best authorities
on the question, for the benefit of those whose want of leisure precludes
them from searching out these facts for themselves.” |
Journ. of Micr., III. (1884) pp. 188-46.
Hitivovusr, W.—Preparing Schultze’s Solution. [Post.]
Proc. Cambridge Phil. Soc., LV. (1883) p. 399.
Hiroxcock, R.—Microscopi¢al Technic. V. Mounting in gelatinous and resinous
media, Amer. Mon. Micr. Journ., V. (1884) pp. 109-12.
See Insects, catching small.
es ra See Mounting, questions about.
Insects, catching small.
[Mounting needle bent into a hook and dipped in alcohol. Dip the needle
into alcohol (or concentrated carbolic acid—-R. Hitchcock) to free the
insects. |
39 ”
Amer. Mon. Micr. Journ., V. (1884) p. 118.
JACKSON, H. E.—Mounting the Skin of a Silkworm.
[Soak in acetic acid for 10 days, then open carefully with scissors from anus
to mouth and wash in water. Soak in weak and then strong alcohol,
follow with oil of cloves, turpentine, and balsam.]
The Microscope, IY. (1884) p. 1338.
Kipper, J. H.—An examination of the external air of Washington.
[Describes and figures an aéroscope in principle “not essentially different
from those devised by Pouchet, Maddox, and Cunningham.” By bending
the tube of the funnel at right angles the glycerine is prevented running
off, as is the case when the smeared glags is set vertically. ]
Journ. of Micr., III. (1884) pp. 182-5 (1 pl.).
Kinesiey, J. §.—Microscopic Methods. I.
[No. II. was given ante, p. 484, the Part containing I. having been lost in
the post. |
III. Hardening and macerating.
Science Record, II. (1884) pp. 108-10, 155-60.
Lavpowsky, M.—Mpyrtillus, ein neues Tinctionsmittel fir thierische und
pfilanzliche Gewebe. (Myrtillus, a new staining medium for animal and
vegetable tissues.) [Supra, p. 652.]
Arch. f. Mikr, Anat., XXIII. (1884) pp. 506-8.
Loew, O.—Ueber den mikrochemischen Nachweis von Hiweissstoffen. (On the
microchemical analysis of albuminous substances.) [ Post.]
Bot. Ztg., XLII. (1884) p. 273.
Mounting, questions about.
[As to the cracking of the covers of Moller’s slides; also as to bubbles, and
note by R. Hitchcock. “Bubbles are occasionally left in fluid mounts,
especially when the cells are deep, under the impression that the air
they contain being very elastic prevents injury to the cell from internal
pressure when the temperature rises. We confess to grave doubts if such _
bubbles are of any benefit whatever.”]
Amer, Mon, Micr. Journ., V. (1884) p. 119.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 659
Necri, A. F.—Coloration des Spores dans les Bacilles de la Tuberculose.
(Staining the spores of the Bacilli of Tuberculosis.) [Post.]
Journ. de Microgr., VIII. (1884) pp. 349-51, from ‘ Lo Sperimentale.’
Piffard’s (B.) Improved Microscopic Slides. [Supra, p. 655.]
Sci.-Gossip, 1884, p. 136.
PoiecnanD, M.—The Microscope in Paleontology. [Post.]
Journ. of Micr., III. (1884) pp. 163-70 (1 pl.).
Prinz, W.—Examen microscopique (1) d’une feuille de papier qui a servi & isoler
les plaques du parafoudre de la station de Lebbeke; (2) des lames minces
d’un morceau de poterie. (Microscopical examination (1) of a piece of paper
used to isolate the lightning conductor of the station of Lebbeke; (2) of thin
plates from a piece of pottery.)
Bull. Soc. Belg. Micr., X. (1884) pp. 152-4 (3 figa.).
Rawpu, T. S.—Results of a Microscopical Investigation of the action of Ammonium
Molybdate and other chemical agents on the vascular and cellular tissues of
about 120 different plants. Journ. of Micr., III. (1884) pp. 155-62.
Ratasoct, J.—Les Diatomées. Récolte et préparation. (The Diatomacee.
Collection and preparation.) Continued.
‘ Journ. de Microgr., VIII. (1884) pp. 342-5.
Rogsox, M. H.—Improvements in Microscopic Slides.
a? experiments of five years ago to make slides similar to Piffard’s,
supra.
Sci.-Gossip, 1884, p. 162.
Section-smoother, a simple.
[Practically identical with P. Francotte’s, ante, p. 315.)
Science Record, II. (1884) p. 112 (1 fig.).
Sippa.L, J. D.—The Microscopical Examination of Milk and Drinking Water.
Micr. News, IV. (1884) pp. 187-9.
Stack, H. J.—Pleasant Hours with the Microscope.
[Examining flowers of Borage, Comfrey, &c.—Ixodes. ]
Knowledge, V. (1884) pp. 430-1 (2 figs.), 472-3 (2 figs.).
StowELL, C. H.—Studies in Histology. III. Section Cutting.
The Microscope, 1V. (1884) pp. 123-7.
+» _ New Apparatus.
”
(Griffith’s Turntable, post. German Microtome. }
The Microscope, TV. (1884) pp. 131-2.
Tay.Lor, T.—Clearing fluid.
[About equal parts of Squibb’s absolute alcohol and Eucalyptus oil forms a
very good clearing fluid for animal or vegetable tissues. When the tissues
are freshly cut, place them in commercial alcohol for afew minutes. Next
transfer them to the clearing fluid, as above described, for a period of
about ten minutes. They are next placed in pure Eucalyptus oil, which
removes the alcohol; a few minutes’ immersion will suffice. It is not
well to keep tissues longer than necessary in the fluid. Vegetable tissues
become hardened when kept several days in it.]
Amer. Mon. Micr. Journ., VY. (1884) p. 119.
Unpernih, H. M. J.—Mounting Infusoria.
[Reports his failures with osmic acid, permanganate of potash, and “ chromic
oxydichloride” acid.]}
Sci.-Gossip, 1884, p. 162.
White Zinc Cement.
[Note on the difference of opinion between Mr. R. Hitchcock and Professor
C. H. Stowell, ante, p. 485. “Perhaps they are not speaking of the
same preparation of white zinc.”]
Micr. Bull., I, (1884) pp. 28-9,
© G30)
PROCEEDINGS OF THE SOCIETY.
Mertine or 1llta Junz, 1884, ar Kina’s Cotten, Stranp, W.C.,
THE PrestpeNt (THE Rev. W. H. Dautinerr, F.R.S.) In THE
CHarr.
The Minutes of the special and ordinary meetings of 14th May
last were read and confirmed, and were signed by the President.
The List of Donations (exclusive of exchanges and reprints) re-
ceived since the last meeting was submitted, and the thanks of the
Society given to the donors.
From
Heurck, H. van.—Synopsis des Diatomées de Belgique—Table
Alphabétique. 120 pp. 8vo, Anvers, 1884 .... .
James, J. B.—Aids to Practical Physiology. viii. and 24 pp.
ByO, Womloms, WI so 55 00 60 «80st
The Author.
Mr. Williams.
Mr. Crisp called attention to the extraordinary character of the
latter book, and read extracts from it (supra, p. 629).
Mr. Crisp described Prof. Zenger’s method of constructing
“« Hndomersion ” objectives by using a mixture of ethereal and fatty
oils, which he claimed enabled the chromatic aberrations to be much
more effectively dealt with (supra, p.616). He exhibited an objective
sent by Prof. Zenger.
Mr. J. Mayall, jun., in reply to Mr. Crisp, said that he had
examined the objective exhibited, and found that it was not a 1/50in.,
as claimed, but in truth not more than 1/8 in. He also found that
the spherical aberration was very imperfectly corrected.
Dr. Wallich briefly described his new condenser, which he ex-
hibited in operation at the close of the meeting.
Mr. B. Piffard’s new slide was exhibited and described by Mr.
Crisp (supra, p. 655).
Mr. J. Mayall, jun., exhibited and described a simple mode of
applying amplifiers to a Microscope (supra, p. 607). Several methods
had been devised, and the one by Tolles was no doubt very good, but
it was expensive. For the form which he now showed he did not claim
any originality, because he remembered to have seen the same plan
adopted, though in scarcely so simple a manner. His was simply a
slide with three concave lenses, which could be pushed through the
tube of the Microscope, so.that either could be used as required. By
this means the working distance could be increased by 75 per cent.
The one to which he had referred had a rotating disk, and he thought
PROCEEDINGS OF THE SOCIETY. 661
the straight slide was to be preferred, as it could be pushed higher
or lower in the body-tube until the best position was found.
The President thought that so far as an amplifier was useful—
and in many cases it was useful—the form which Mr. Mayall had
exhibited was a good one.
Mr. Conrad Beck exhibited and described a new form of Micro-
scope lamp (supra, p. 628).
The President thought that the lamp was most ingenious and
satisfactory, and that many of the arrangements were such as would
be of great utility to working microscopists.
Messrs. Swift’s lamp, a cheaper form of the one shown at the
March meeting, was also exhibited by Mr. J. Mayall, jun.
Mr. F. F. Hazlewood’s note was read as toa human spermatozoon
with two tails.
Dr. Anthony confirmed the statement that the occurrence of this
variation from the normal type was not unprecedented.
Mr. J. Brennan's further communication on the Potato-blight
Insect was read.
Mr. Cheshire described an organism which he exhibited, and
which was identified by the President as a Spirochete.
The President said the specimen showed considerable variation in
the length and number of the spirals.
Mr. E. H. Griffith’s new form of turntable was exhibited and
described by Mr. Crisp.
Dr. Anthony read his paper “On Drawing Prisms,” and illus-
trated the subject by numerous specimens of drawings of micro-
scopic and other objects.
The President said the subject of Dr. Anthony’s remarks was one
of great practical importance to all who desired to make microscopical
drawings correctly. He had used various forms himself, such as
Wollaston’s, Zeiss’s, and Nachet’s, though he thought he might say
that he inclined towards the Wollaston, with which he had made his
drawings of the flagellum of Bacterium termo. Although at the
time he did not know why, he had found it quite necessary to tilt
the drawing table in the way Dr. Anthony had described.
Mr. Crisp exhibited, in connection with Dr. Anthony’s remarks,
an ingeniously contrived drawing rest, which had been sent some
time ago by the Geneva Physical Company, and which he thought
met the want which Dr. Anthony had felt. It was an adaptation of
the principle of the one figured at p. 565 of vol. iii. (1883) of the
Journal.
The President said that when working he had a somewhat similar
662 PROCEEDINGS OF THE SOCIETY.
arrangement made with a tripod on which the instrument was placed.
For drawing he had a small table at the level of the stage mounted
on a swivel, so that it could be used at any angle. He never worked
below the level of the stage.
Mr. Michael said he had used the camera lucida a great deal in
making drawings of all kinds, and his reason for rising was that it
seemed to be taken for granted that Zeiss’s form of camera was not
so good as others. So far as his own experience and work were con-
cerned, he had found it to be about the best, and he must confess
that he did not see the image of the brasswork as had been described.
His plan was very simple, for he used a drawing-board propped up
upon books, so that the board was practically a continuation of the
stage of the Microscope. If he thought that the image was not true
he put in a stage micrometer and drew the image of it, and if this
was done in two directions and both drawings were alike he knew
that the projection was correct. As to the difficulty of seeing the
pencil, he found that this varied very much with different persons,
and that when he could not see it, others could do so with perfect
distinctness. He liked to work with two lights and to have the light
on the drawing-board much brighter than that in the Microscope;
but on the other hand he found there were many persons who under
these conditions would find that the image of the pencil overpowered
the light from the object. He certainly thought the Zeiss form the
best for ordinary mounted objects and for all such as were not
mounted in fluid, whilst if it was desired to draw an object mounted
in fiuid there was nothing better for the purpose than the Nachet
form. The camera lucida, it should always be remembered, was an
instrument for drawing outlines rather than filling up details.
Mr. Beck said that the difficulties arising in connection with the
camera lucida had from time to time come pretty prominently before
him. There were two central forms which might be taken as types;
one of these was the neutral tint reflector, and the other was the
Wollaston. The neutral tint glass inverted the image so that a
drawing made by it of anything which had the heart on the right
side would be drawn as if it was on the left side. The practical
difficulty met with in the use of the Wollaston camera was not
because the Microscope had to be used in a horizontal position, but
because of the difficulty experienced by some persons of seeing the
point of the pencil. This might arise from the fact that very
frequently persons used a large amount of light so that the pupil of
the eye was very much contracted. He thought nothing could be
better than the old Wollaston form; he had never himself found any
difficulty in using it, and in spite of all the new contrivances which
had been brought out, a large number of persons still used it and
preferred it.
Mr. James Smith said that with regard to the difficulty which
Mr. Beck had stated some people experienced in seeing the point of
the pencil, the best plan was to cut a very fine point to the pencil,
and then dip it into black ink, which would render it perfectly plain
on the white paper. With regard to the adjustment of light, it would
PROCEEDINGS OF THE SOCIETY. 663
be found that when making drawings by daylight it was a good plan
to illuminate the object by the light of a small lamp, and to let the
ordinary daylight fall upon the paper.
Mr. Dowdeswell’s paper ‘On some Appearances in the Blood of
Vertebrated Animals with reference to the occurrence of Bacteria
therein,” was read by him (supra, p. 525).
Prof. Bell said that Dr. Timothy Lewis who had been making
some observations in India opened a dog and removed its two kidneys ;
one was placed directly into warm paraffin and left to cool, and the
other was examined at once; the latter was found to contain no
bacteria, but the one which had been put into the paraffin was found
to be swarming with them. This fact had not been referred to by
those who were at present examining into the nature of cholera
germs, but he thought it contained a moral which applied to all forms
of disease.
Mr. Beck considered the question to be an extremely interesting
one. If what the Secretary had said—that the bacteria were the
result and not the cause of the disease—was well founded, the same
might apply to other diseases.
The President thought that it was not Mr. Dowdeswell’s intention
to say that there were disintegrated corpuscles, but that there were
pseudo-bacteria. In the case of splenic fever the specific forms had
been seen, and it had been not only proved that when introduced into
the system they would give rise to the disease, but that when they
had been filtered out the disease could not be so communicated, so
that it was clear in this case that the bacteria were the absolute cause
and not the result of the disease.
Dr. Anthony and the President further discussed the paper.
Mr. Oxley’s paper “On Protospongia pedicellata, 2 New Com-
pound Infusorian,” was read by Prof. Bell (supra, p. 530).
Mr. C. D. Ahrens’ paper “On a New Form of Polarizing Prism ”
(supra, p. 533) was, owing to the lateness of the hour, taken as read,
Mr. Ahrens explaining briefly the principle of his arrangement by
means of a black-board diagram.
The President said that at the last meeting of the Society it was
mentioned that the American Society of Microscopists would hold
their meeting at Rochester, N.Y., in August next, and he had been
appointed, in connection with Mr. Glaisher and Mr. Bennett, to
attend as representatives of the Society. Since then the American
Association for the Advancement of Science had invited the Society
to the meeting to be held at Philadelphia, and it had been proposed
that the same gentlemen should attend that meeting also on behalf
of the Society.
This proposal was approved unanimously,
664 PROCEEDINGS OF THE SOCIETY.
Prof. Bell mentioned that the Victoria University of Canada
had intimated their intention of conferring an honorary LL.D.
degree upon their President during his visit to Canada, and he con-
gratulated him on behalf of the Fellows on the honour thus proposed
to be conferred.
The following Instruments, Objects, &c., were exhibited :—
Mr. Ahrens :—New Polarizing Prisms.
Dr. Anthony :—Prisms and drawings illustrating his paper.
Mr. C. Beck :—Microscope Lamp.
Mr. Cheshire :—Spirochete.
Mr. Crisp :—(1) Zenger’s Endomersion Objective; (2) Objective
by Nobert, with curious form of correcting adjustment.
Mr. £. H. Griffith :—Turntable.
Mr. J. Mayall, jun. :—Microscope with sliding amplifiers.
Mr. Piffard :—New Slide.
Dr. Wallich :—Condenser.
New Fellows:—The following were elected Ordinary Fellows :—
Messrs. T. Breeds, Arthur EH. Davis, Ph.D., Robert Harwood, and
James West; and Mrs. Catherine Crisp, the Hon. Mrs. Peek, and
Mrs, Anne Wilson.
a5 The Journal is issued on the second Wednesday of
es February, April, June, August, October, and December.
J ~@
Ser. ITI. To Non-Fellows, YQ
Vol. IV. Part 5. OCTOBER, 1884. | Price 5s.
Up
JOURNAL
OF THE
ROYAL
MICROSCOPICAL SOCIETY:
CONTAINING ITS TRANSACTIONS AND PROCEEDINGS,
AND A SUMMARY OF CURRENT RESEARCHES RELATING TO
ZOoOoLoGeyTYT AND BOTAN YW
(principally Invertebrata and Cryptogamia),
MICROSCOPY, Sc.
Edited by
FRANK CRISP, LL.B., B.A.,
One of the Secretaries of the Society
and a Vice-President and Treasurer of the Linnean Society of Londow ;
WITH THE ASSISTANCE OF THE PuBLIcATION COMMITTEE AND
A. W. BENNETT, M.A., B.Sc., F. JEFFREY BELL, M.A.,
Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College,
8. O. RIDLEY, M.A., of the British Museum, JOHN MAYALL, Joy.,
anpD FRANK E. BEDDARD, M.A.,
FELLOWS OF THE SOCIETY,
if
-
“
¥
a .
4
7
‘
WILLIAMS & NORGATE,
LONDON AND EDINBURGH. bu(a)
Goh,
mse At
= BY WM, CLOWES AND SONS, LIMITEN,] [STAMFORD STREET AND CHARING CROSS.
CONTENTS.
——eo7g,00——_—>
TRANSACTIONS OF THE Soorety— Tse
XVL—RESEARCHES ON THE STRUCTURE OF THE Caines OF
Diatoms (continued). By Dr. J. H. L. oe ie X.
and XI. and Fig. 119)...
XVII. —On Drawine Prisms. By J. ‘AndlOny. MD. Cantal
FROP., F-RMS. (Figs. 120-22)...
PAGE
665
. 696
Summary oF CurRRENT RESEARCHES RELATING TO ZOOLOGY ANR
Borany (PRINCIPALLY INVERTEBRATA AND Cryprogamia), Micro-
soopy, é&c., INCLUDING ORIGINAL Communications From FenLows
AND OTHERS .. oe oy os se oe ae ee oe oe oe
A Zoouocy.
-Embryology of the Sheep BN geist Babe eet ot sary be aa ee eee
Development of. the Generate Organs Tres emer ese
Spermatogenesis .. .- sin coe! Rowe power ee eal te ol a
Factors of Sexuality . NE ne ign ree can er eee
Rudimentary Placenta ‘in Birds .. ae etea eal ema
Permanence of larval conditions in Amphibia Praia reer iN iia
Embryo Fishes .. + SSE EC AUER TTR I L.
Development of Viviparous Minipod ce Pe ee a
Formation of and Reactions of Nuclet .. 21 0. ee ee een
Indirect Nuclear Division .. ce 2 aaa ele monies
$: Nucleus of the Auditory Bpitheliwm of B Batrachians Sa neereh Saas eae
Epidermis of the Chick .. Preanoriienn ee oye ten
Scales, Feathers, and Hairs Spee Tate ahs ee 5
Locomotion of Animals over smooth Vertical Surfaces Feigvand & ude Someta
Zoology of the Voyage of the‘ Alert? 1. su ee oan we te
Origin of Fresh-water Faune .. 1 s+ ee ae oe ae ne ae
Pelagic Fauna of Fresh-water Lakes - cr
Lowest and Smallest Forms of eae as revealed by ‘the modern Microscope .. .
Intelligence in the Lowest Animals .. 21 oe se we vin aU eR anSe
New Type of Mollusc... .. ey
Taking-in of Water in relation to the Vascular System of Mollusca.
Eyes and other Sense-organs in the Shells of Chitonidz Se uae ee
Renal Organs of Embryos of Helix. .. se an ne oe we
Nervous System of Parmophorus australis .. .. 2 + ;
Organization of Haliotis. .. . Gee pede eats vonte yon he eee aes
Absorption of the Shell in Auriculide —.. gu SiR, cat eles aan
Development of the Digestive Tube of Dimacina si pee Cas en aaa
Simple and Compound Ascidians .. .. eer! cae toe EE
Digestion in Salpa 506 ice veer Br Gee ae Oe a ae ne
Fresh-water Bryozoa .... LOC a tsces, Cia tay omar tee
Supposed new species of Cristatella .. 2 URE
New Type of Elastic Tissue, observed in the Dine of Eristalis.. .
Submazillary of the Jaw of Mandibulate Insects .. .. 1s ss os
“Structure and Function of Legs of Insects .. Se | ae
Organs of Attachment on the Tarsal Joints of Tnsects cs wk a eee
Locomotion of Insects on Smooth Surfaces. .+ 6s ae oe ews
Organs of Flight in the Hymenoptera +. 41 se eee tee
Poison of Hymenoptera and its Secreting Organs .. 1 6. ae oe
Development of Cerocoma Schreberi and Stenoria apicalis ye Gate ieee
Dipterous Larve.. — «. eda Risto ik aces eae cba a ale are
Larve of North American Lepidoptera .. Seek Rae tk eo aah eee
Drinking Habitof a Moth.. .. + SG Atk ay eee
Michael's British Oribatides MLSoeivuan Gewac C amis aera apne
Stomach of Podophthalmate Crustacea .. 11 05 su an op we
Significance of the Larval Skin in Decapoda... ... 2. «+ ee
New or Rare Orustacea .« os se nee we we | os we
New. Type of Hérudined cco oe = ae ee an an tae Sen as ee
Structure of the Branchiz in Serpulacer .. Ue cae
Structure and Development of rb ihiariaak Dendrocala RY Gales al ee
Classification of the Rotifera .. .. wee Stew Foes CUR rem ERNE
Constitution of Echinoderms ~.. (1. 06 5 oe \ oe te on tet
PGi tgs vers ee Sak as SAU kes ts Seen os ORE eee ey
(C8)
_Suamany or Current ReskArouss, fea 8 A
5, Anatomy of Lareat SOME Bra sip 8 SESE ae ESE RET Ue heals TE
_. Notes-on Meduse... |... Giver cae) SGP bers pi pie WR a ee eke pec’ 2 heer MaleD
" Revision of the Madreporaria SEtk atk Oe eee a ART pha ed oak hee OD
: Bee ee es ee Baily eet a telat oye cat a eager sie 1 Oe
Siliceous Spicules of Sponges Bora dn tity a as SE
- Fresh-water Sponges and the Pollution of River-water Sei ak oes UE
New Infusoyia IR PR oe eee Roepe cae Peery ten Patsy AAMC ner Ci ES |.
” Pardsitic Peridinian .. Ss ial A ia aaa ae Laos Sat te hed is a Ee eae
Observations, on Flagellata ... Fe SecA woud eo Web oet Male aan Saree ema e
_ Geometry of Radiolaria SS wan /ig a ORE Deo hs EE Oty t Dare ig eo
- Polythalamian from a Saline Pond . ig ne See) ell. Cal iain ete ea
_ Nuclear Division in Actinospherium eichhornié. .. - .. .. 495 goes er eee
- Parasite of the Wall of the Intestine oe the Horse Joy) LER AE ah hs ete ee
secant “ Fozoon” ie cae Meg as Le beet Raine aE
-
Borany.
Continuity of Protoplasm ..
Osmotic Poiter of Living ‘Protoplasm ey weit oe
Structure of Pollen-grains SSP eae Oar ee aE eS
' Seeds of Abrus prxcatorius .. re
- Oe eiaparetiee Anatomy of Coty wiidons and i Enddepern ees
~~ Underground Germination of Isopyrum thalictroides .. ..
' Stomata of Pandanacer ..
~~ Changes in the Gland-cells of Dionza muscipula during Secretion
__ Septal Glands of Monocotyledons °3.- 0 ae ae ne aa a
~ Secretory System Of COmBOnl Be ea Geel eevee en ee en
We * Chemical Constituents of Plants ©... 2. we ee
phe “Structure of Leaves 2. 1. ee ee ee eee
~ Transparent Dots in Digber hg ee
- Seeretory System of the Root and Ren ee
_ Anatomical Gtructure ofthe Root. og -8 8 5 ean ae a ae
Growth of Roots’:. *.. ae ie ee
‘ *" Growth in length of decapitated and uninjured Roots .. P
roo « Geotropion and Hydrotropism of Hoots .. + s+ +
j - Water-glands and Nectaries .. . sng. Sly tos
~ Folds of Cellulose in the Epidermis of Pitala’ Siena ee
~ Anatomical Structure of Cork-woods alae take Po nay ett maT
- _ * Filiform Apparatus” in Viscum cle
~~ Ae¢tion of Heat upon Vegetation ie
_- \ Relation of Heat to the Sexes of Floivers 3) ‘3: RA
Influence of Light on the Structine of the Leaves of Altium ursinum
ee SE sr, aect of Light and Shade on Fea ca PB ee eae a
- .. ~ Movement of Water in Plants .... Rae cas aie
% fs: Movement of Water in the Wood 2. ek a as
~ Measurement of Transpiration .. Sort esa oak ie
ple | Betaiaton of Ozone by Flowering Plants Deity MORTARS ake vata
* Acids in the Cell-Sap’.. Eo iw goog Se
eS Bt Colouring Substance from Choro hyth ct bens tame ee
7 a eotalline Chlorop phy mee o- ea “ oe a Py *e 7
Gh stals and Crysta ee a :
gta Ge On Gao iee
Tit ie Cli te GaN Mag Faas a core
CE PUIG co hee ig ise, een knee Salou. Wane
ie AGORA PIQUA EE oi foe NG 8 oct) oak np ones > we: os pa
t: _, Bish caught by. Utricularia ye Wen Pye , #6 ae - ‘we -
Yims Oe apie ‘Cryptogams. 1. 6. oe we ae oe ge
oa |) Fartltsation oe o. os oe or wa iee dein
7 Male Misaadee of Moves s0 04S ee be
ae. aquereus and Jarnes's Moses of North America... yids on oh tae
Supposed ion and 9 al is Nitrogen by. Pungi oa Rowe
Feet itic on Drosophila . a ety
f
> ” rd * ae
“ aa fas
ge
e
Fermentation as y
. ae Se ge a a
- Somany OF Oiihanr REsgARCHES, ‘ke ON ne:
Bacillus of Cholera sees .\%p- Se bs ee he ow aes
3 bies ee so ‘eo as ec. ee ot = 6o - oe on.
Etiology of Tuberculosis. - «. gen ee tee a eee
Bacteria and Minute Alge on Paper Money .. CRE es
Grove’s SEB of the Bacteria and Yeast Fungi? sek ue ee
Protochytrium Spirogyrz, a new Myxomycete (2) 4. +1 oa
Substratum of Lich ens eo «swe ae eo be oe oo | ee
Huymenolichenes ose. 3s Aies ee ee wes ers bess ea bs
Fresh-water Phzospore ve es oy oe sh 60 eek
Nostoc ees oe ee wae 1 se ee = oe Sere ee wé
New Chromophyton Se Cader sey See ee
Wolle’s Desmids of the United Bikes: San oe
New Diatoms—Diatoms from Stomachs of Seawe Oysters poche ae
Structure of Diatoms eo ee eo oe eo : eo ee oe eal oo ise
Microsoory.
Albertott#’s Micrometer Microscope (Fig. 123) - .. Soar cae
Baumann’s Callipers with Movable AONE, and Fixed Micrometer Re
(Figs. 124 and 125)_ & We ieee © Saale
: Geneva Co.'s Microscope Calipers (Fig. 126) Sige ood Jae nile
fe ee ne Grifith’s Club Microscope... oe ee eo “ee : ‘eon ee ee
eS ' Nachet’s Class Microscope (Fig. 127) eee ey
NG Pee Nachet’s Microscope with Large Field .. Ae pee
PEE Ain Stephenson's Aquarium Witipomtope (Fig. 28) a " eer
Swift and Son’s Oxyhydrogen Microscope (Fig. 129) Sai te
Nelson's Hydrostatic Fine Adjustment (Pigs. 180-182) | EN a
ee he Griffith's Nose-piece (Fig. 133).. —.. eye,
tee a Sele Hyé-piece with additional Lene “Ge a ‘Condenser Slee ea
Pa DiGlOmekOOPe™. ey. ek Sok oul 9a Dee ees ae, Came
ae Flardy's Collecting Bottle 552 ose <0 ican 2G b0k- specced en ea
es Eye-piece Amplification .. ein hare aa nes Suen
ee Illumination and Focusing in Photo-Micrography Seen
~~ Mitchell's Focusing Glass for Photo-Micrography .» ov «» ° «
-. Photo-Micrography. in Legal Cases (Fig. 134) se ee ne oe
~ American Society of Microsopista +» 11 +e +e oe nh ae oe
: Health Hxhibition se we. ee i apes | eo ee ee ee et” °
Killing Infusoria bo oo o> oe ee eo oe oe oe Ae
“Perchloride of Iron .. Sas
Mounting of Foraminifera—New Slide for Opaque Objects
ere lin as a Reagent for Pec satis Non-suberized Celtutoe
é! ‘NES os ve eo oe PO ee, oo be lee oo ve 6
Canarine for Staining .. 2h ate
Cultivation of Bacteria upon the Slide Giga. "135 aad re Testes
Staining of Schizomycetes in Sections and Dry Preparations ..
Staining Fluid for Sections of Seid eae aes VES aa aeeed
Methods. of Imbedding (Figs. 187 and 138) .. 0 4. se te
_ Hoffmann’s Imbedding Apparatus (Fig. 139) eee Swe cece hoee tee
’ Celloidin for Imbedding .. iSeeamare pha toey wae p
~ Reichert's Microtomes (Figs. 140 and 141) Bias inter. aspen oul aeas
_ Decker’s Section-smoother (Fig. 142 2 a ee ee
Griffith's 3 Turntable (Fig. 143) oo” ee oe oo ge , ie z : 6, aS
Reversible Mounts a | Peritersl 5 oe. _@e eo ee eo ee
Hinman’s Device for Mounting .. Bae es tag yk PRLS, Ps eet
Preparing Schultze’s Solution 5. a pe) ov ae jae ee we
2 * Styraz and Tiquidambar . es ee Re pe ae 5 a0" & RS 0 oe Me oe.
i , Preparing Shellac Cement .. ee ee oe a op HES ° « : Ye Sate ae
: ae Coating Diatoms with Silver oo) ee kgs Saar y hk eee oe oe nn pies
Rest ; Lyon's Mailing Case. pee
~~ Action of Reagents tn ihe aueortindantton of Vegetable Fibres eS
" Reagents for Tanning in Vegetable Cells... .. se ae ae es
Microscopical Examination of Chestnut-meal .. ee ae ae
Microscopical Investigation of Dyed Cotton. Hubris Se terme
- Microscopical Examination of Water for Organic Tmpurities —
Changing the Water in Aquaria contaming Microscopical Organism
> pees Micro-Chenical Test for Sodium Spee TE Ores ee iS
MRO Micro-Chemical. Reaction of Solanine eens ee eae
: Beas Size ae. oe oe ee oe on. ae op ee ae es as 3 wp
eee
“ROYAL MICROSCOPICAL SOCIETY.
COUNCIL.
ELECTED 138th FEBRUARY, 1884.
PRESIDENT.
Rev. W. H. Datiinerr, F.RS.
VICE-PRESIDENTS.
Joun Antuony, Esq., M.D., F-R.C.P.L.
Pror. P. Martm Duncan, M.B.; F.R.S:
Jawes Grarsuer, Esq. F.RS., FRAS.
ee. STEWART, Esq., M.B.CS., F.LS.
TREASURER;
-Lrovet §. Bratz, Esq., M.B, F.RCP., FBS.
SECRETARIES. §
os Crisp, Esq., LLB., B.A. V.P. & Treas. LS.
Pror. F. Jerrrey Bex, M.A., B.Z8.
Twelve other MEMBERS of COUNCIL.
Aurrep Wiur1am Bennett, Esq., M.A,, B.Sc., FLS.
Rosert Brarrawarrs, Esq., M.D., M.R.C.S., F.LS,
_G. F. Dowprswett, Esq.,. M.A.
«J, Wmram Groves, Esq.
- ‘Sonn E. Incren, Esq.
Joux Marrnews, Esq., M.D.
Joun Mayatn, Esq., Jun.
— Ausrrt D, Micuan, Esq., F.LS.
~- -Jonx Muzan, Esq., L.R.C.P.Edin., F.LS,
~ Wrsaw Muar Onp, Esq, MD. F.R.CP.
Unsan Prrronarp, Esq., M.D. AN: : : fe es A ee
Wuuam Tuomas Surrorx, Esq. es ame od
LIBRARIAN and ASSISTANT SECRETARY. oes Tae
I. Numerical Aperture Table.
‘The “ ApertuRE”’ of an optical instrument indicates its greater or less capacity for receiving rays from
transmitting them to the image, and the aperture of a Microscope objective is. therefore determine s
between its focal length and thé'diameter of the emergent pencil at the plane of its emergence—that is,
diameter of.a.single-lens objective or of the back lens of a compound objective. pt oes iat oe
This ratio is expressed for all media and in all cases by 7 sin wu, n being the Yefractive index of the medium and @
semi-angle of aperture. ‘The value of m sin w for any particular case is the ‘*mumerical aperture” of the d
Diameters of the _ Angle of Aperture (=2 4). | —‘Dheoretical |=
* Back Lenses of various e : - = Tilumi- |: Resolving’
Dry and Immersion Numerical} , > Water- | Homogeneous-) nating Power, in
Aperture. |_| Dry ; : 3 op
AB eee Immersion| Immersion \| Power. | Lines te an Inch;}
(nm sin w= a.) | Objectives. | Opicctives.| Objectives, | (a3.) | (=0°5269p |
(7 =1.) a5
AD aay Zo: (bs =33.)\. Gul 1°52.) he. ves == linediny
Objectives of the same
Power @ in.) —
from 0°50 to 1°52 N A.
|
ae 98 180° 0’ 2°310 2b tO, Ved,
| wef 161° 23% | 2-250] 444,600
oe ey 1539-39" | 2°190 | > 142,672.
Pere eee vide vee yaa Cre
oe | Se Sh 422 40% | 22 074 ees ae
ss 188% 19" 2-016)" 136,888
= ye - | 1842 10" |1-960.)° 784,960
COCO OT
53 ne 130° 26" | 1-904]: 138,032.
ae s | 126° 57" | 1-850] -. 13%, 104
as -} 23° 40". | 1-796! 1292176
w. 1 180° 0’) 122° 67 |1-770| — 128,972
s 165° 56"| 120° 38 | 1-742) 127,248
ve | 155° 88"|- 117° 84’ }1-690; 125,320 ©
> ye > (1480-28) 114° 44” 17-638 3,
as 142° 39'| 111° 59’ | 1588} 121,
.. _ /187° 86’) 109° 207 | 1-538
w | 1880 4’| “106° 45’ | 1-488}
Ny |198° 55") 104° 15" 1 +440 |
yo -- 1125°-8'| 101° 50’ | 1-392
«© | 121° 26") 99° 99" 41°46] 412
%; 1°300| 1
*
¢
HAHAHA ADD AOIIIIIOMDDHDDODODDOODOOCOH EHH UYNYWNWHM
CVUBDAROVKADOWKHG DOV KABDOWHADSOWKADOVHAVDOWRADOWVWBADOWRADOW
2
29900999999 90900909 000 COCR PEER HEHEHE HH BHM HME Hii
_ -Eximpre:—The apertures of four objectives, two of which are dry, one water-immer
would be compared on the angular aperture view as follows:—106° (air), 157° (am),
‘Their actual apertures are, however,as §; Re 300% tx) 98
"numerical apertures. aie get ea aD ge
(1.) Lrygab.
' Micromillimetres, §c., into Inches, ge.
Conversion of British and Metric Measures,
Inches, §c., into
; ing Micromillimetres,
a B ins, | mm. ins. | mm, . §¢,
ni nets, / 1 -000039; 1 “039370 | 51 2:007892| ins, —p
Besacties. 2 -000079| 2 -078741| 52 2°047262 | . 2 - 1-015991
Sea 8 000118; 38 ‘118111; 58 2-086633 { (2. 1:269989
2 4 +000157| 4 "157482 | 54 2:126003 | "i" 1-693318
. 5 -000197| 5 "196852 | 55 2°165374 | 7°" 9-539977
aT - ~ 6 -000236| 6 -236223 | 56 2°204744 | 7°29 9.899197
| 7 -000276| 7 -275593 | 57 _ 2°244115 | a 8-174972
a 8 -000315; 8 *314963 | 58 2°283485 | 72, 3°628539
3 9 -000354| 9 -354334 | 59 2°322855 | 11 4:933005
" ~4) 10. -000394 | 10 (1em.) +393704| 60 (6cm.) 2°362226] ~1 5§-079954 .
i -000483 | 11 -433075 | 61 2°401596 | soon 67349943
| “000472 | 12 -472445 | 62 2:440967 | sop _87466591
x -000512 | 13 “511816 | 63 2°480337 | sooo 12°699886 ~
+ ; 1 . ;
=| | -000551 | 14 651186 | 64 2°519708 | ross 20°399772
BI | 000591 | 15 *§90556 | 65 2-559078 : 098002".
| “000630 | 16 -629927 | 66 2598449 | Fed ee
* -000669'| 17 -669297 | 87 2°637819| soo * pete
>| leg! -000709 | 18 -708668 | 68 2-677189 |. oe (etaee
5 : “000748 | 19 “748038 | 69 2°716560 | 380°
= 000787 |. 20 (2em.) °787409| 7O(7 em.) 2°755930 ae seat
a -000827:| ‘21 “s26779) 71 Bie ato 108349
=| Oe ele es +000866 |. 22 - *866150 Le *OT2574
) ~000906 | 28 -905520| 73 2°874042| 23°". .ogagee |
A | eee eee eee| eae
a 000984 | 25 : : : *126999.
- -001024 | 26 1-023631 |. 76 2°992153| 22° .769382 |
= 001063 | 27 1-063002 | 77 87031523; [2° «953998
-001102 | 28 1°102372 | 78 8°070894 Py... 7507995.
| % “001142 | 29 1°141743 | '79 8:110264| 2° 4-015991 |
5 i “001181 | 80 Bem.) 1181113} 80 Bem.) 37149635}
a} -901220| 31 1220183 | 81 3-189005|
i} |. |) + 82. -001260 | 32- 1°259854 | 82 3228375 | Ts
mlb *001299 | 33 1:299224) 83 3°267746 | as
z 001339 | 34 1°338595 |. 84. 3°307116| a” 27939977
a *001378 | 35 1:377965 | 85 3°346487) =
| -001417 | 36 1:417336 | 86 3°885857|- @
aa i -001457 | 37 17456706 | 87 37425298} ete
ati 001496 | 38 1°496076 | 88 3°464598 | ¥
z 001585 | 39 1°535447 | 89 35038968) = +
:| re "001575 | 40 (4em.)1°574817| 90 9 ah) 3-543339 oe
ole 001614) 41 1°614188| 91 3*582709 Ss
ml 001654 | 42 1°653558 | 92 * 8622080}. a.
4 -001693 | 43 1-692929 | 93 3-661450]
: _ 001732 44 1-732299 | 94 3°700820} a.
4 “001772 | 45 1-771669 | 95- B-740191}g
+ -001811 | 46 1°811040| -96 3°779561 |< ay
: al - *001850 | 47 1°850410 | 97 8°818932] gt
- -*001890 | 48 1°889781 88 3+858302} yee
4 -001929},49 1929151 | 3:897673 | *g
t -001969 | 5O (5 emi.) 1-968522 | 100 (10. em,=1 decim.)| a
z 002362}. 7 ee
mt 002756 decim. ins, eae se
=| 008150 1 3987043 Riga
+ 003543 2 7874086 S egeare
=I 7003937 3 11°811130 © ‘ Pee ante
: "007874 4 15°748173 Mi Bac
"011811 5 19° 685216 » ee te a GaN
1015748 6 23 622259 phar
“019685 7 277559202 ei at
°023622 8 31496846. A We
2027559 9 35° 433389 nN
031496 10 qt babs 89-370432 late
°035133° ee 280869 ft, Bae Gane y
=1mm.)) = 1:093628 yds. lyd.=
f ~~ ¢ ’ oi lmd
“Containing its Transactions and Proecings :
AND, sb SUMMARY. OF CURRENT: RESEARCHES RELATING TO”
_ ZOOLOGY AND BOTANY ee
(principally Invertebrata and Cryptogamia),
MIOROSOOPY, Go
_. Edited by
Frank Crisp, LL. HBAS
“one 0 of the Secretaries of the Society and.a. Vice-President and Treasurer of the
as Linnean Society of ‘London 5. 2 = :
” wrrn THE ASSISTANCE OF THE PUBLICATION Comers AND :
ay W. ‘BENNETT, M, Ay BSG fo Ao, JnrvREY Betz, M. ce
Lecturer on Botany at St. Thomas's Hospital, Professor. of Comparative Anatomy i in Kings College,
8. 0. Ripuey, M.A., of the British Museum, JOHN- Mayan, Ts Se
; and FRANK E. Bepparp, M. A. : es
=e FELLOWS OF THE SOCIETY.
TH 8 J ae is published bimontidy: ‘on the ae Weancsday of ee
3 nths of February, April, June, August, October, and December. It :,
ve es in size, according to convenience, but does not contain less than
ets (144 pp.) with Plates and Woadonte: as phe vous The ee < me.
non-Fellows i is 5s. per Number. -
The . Fournal comprises: :
(1) The Transactions and. <he Pihaceacs of fies Society ine
‘being the Papers read and Reports of the business trans-_
_* acted at the Meetings of the Society, including any
gas Seer or. discussions on the Bubjeoks brought ©
- forward. - -
ee @). Suamtary of CURRENT eaccnee relating to Z
and Borany (principally Invertebrata and- ‘Cryptogamia,
with the Embryology and Histology of the higher Animal:
and Plants), and Microscory (properly so called):
_ abstracts of or extracts from the more importan:
articles relating to the above subjects contained in the
_ various British and Foreign Journals, Tinea ee
from time to time added to ae Aubrary. ee
) dihork of Papers printed in the Transactions : are entitled fs 20 copie
of their communications gratis. Extra copies can be had at the price ‘
12s. 6d. per half-sheet of 8 pages, or less, including cover, for a minimu
number of 100 copies, and 6s. per 100. plates, if pi pbc
P.0.0. is Tequested. 3
“AIL communications as” to. the Tournal ‘should be 1ddre
(9)
J ICROSCOPIOAL SOCIETY'S TRANSACTIONS (8 vols. half-
_ ealf) ; Quarreriy Journan or Micnoscorioan Science (16 vols.,
. half-morocco) ; and Monrany Microscorican JournaL (18 vols., half-
calf) for SALE. Price £20.
Apply to Mr. J. Wesr, at the Society’s Library.
; _ ROYAL MICROSCOPICAL SOCIETY.
MEETINGS FOR 1884, at 8pm. @
Wednesday, January .. .. 9} Wednesday, May .. .. .. 14
LI mr re gs Te
Frsruary .. .. 18 i > DUNE. 6.2 ee
; tAsoal Ueriing for Election of 3 OoropEr 3.245226
jc SIRES Ge Couey ee Novemprr ., .. 12
i on Mapa © sys. Ae DECEMBER 10>
= Arig sey 8 ie Aes
_-—Ss«- PHE “‘ SOCIETY’ STANDARD SCREW.
The Council have made arrangements for a further supply of Gauges. __
and Screw-tools for the * Soorery ” StanpArp. Screw for OBJECTIVES.
The price of the set (consisting of Gauge and. pair of Screw-tools) is "ee
~ 12s. 6d. (post free 12s, 10d.), Applications for sets should be made to this ea
Assistant-Secretary, .
For an “explanation of the intended ee 6 of the gauge, see Journal of the 2 Te S
_ Socity, I, (1881) pp. 548-9,
WMT Kh a
- THE BRITISH MOSS FLORA, Bae.
By R, BRAITHWAITE, M.D. a
Paw yull, ToRTULAC#, is now ready, price 6s, Subscriptions to Sect. 3 Cs 6d. Dee
may be sent to the Author. ,
The previous Parts may be had from the Author, at 303, Clapham Road, "Lostline
Sie. ret au i ae
*.
ADVERTISEMENTS FOR THE J OURNAL.
Mr. CHARLES Relcaws, of 75, Chancery Lane, W. 0.4 ig ne ates
and Collector a Advertising Accounts on nae of the Brag ae 5a
~
MANU UFAOTUR RER
ORS
- SCIENTIFIC
al NSTRUMENTS,
———e
e LATE
j PARTNER WITH
a did. BECK.
a PATHOLOGICAL
= AND
: PHYSIOLOGICAL |
PREPARATIONS. .
| a
SS tame
~ Students and
STAINING FLUIDS. Amateurs,
Pe ANDIALL oy \ s: e Tae
-ACCESsoRIES %4\ a ILLUSTRATED
ome fo earacoaue,
100.1 NEW BOND STREET, :
~ LONDON, We 3
oo ON, B. SPEOTACLESI! | cee
OCULISTS’ PRESCRIPTIONS RECEIVE PERSONAL reo
gh
“AGENT ror W. H, BULLOCH, CHICAGO, ILLs., USA. at tea
: R. H. SPENCER & CO., NY.) U.S.A. yaaa
» \ JAMES L. PEASE, MASS.; USA,
» Mw PRAZMOWSKI, PARIS, .
Ree es ee M. A. NACHET, PARIS. Hd
JHA. Flogel del.
JOURN. R.MICR. SOC. SER. IL. VOL. IW. PL.xX.
ae
ri Ne oerey
Bemoemals
Ree
DETTENE
Achnanthes.
JOURN FR MICR, SOC, SHR. VOL IVeli yar
wr.
ds
42.
43.
joo 22 5,
go? a oN
<)
Ko}
%&
is)
a
re
te}
%,
a
9
@
: Preven
Vamomor tPF,
Wr
Yr
%
aa
© : REO
H o® i
ca
&
o
)
&
3
°
%,
%.
Qe -
BB t
cae)!
=
re
ot
fe)
a Tay
——
Se °
S 9
P
k
“
.
.P
Cos
jaqannnnenerttarsnnsa te nonrgsergnyantaanravesensersaseeaneasnntrens 8S OEE wea agg,
ott .
ae
on?
“
capes
o
#0 anecenceencs aagwatEshe2ts+e ones eaceesasse cag oenens qnaanagee™
(N)
.
4
a
a
In S®VSoOBTSVS AVS
West Newman & C® lth,
JHL.Flégel del.
Achnanthes.
JOURNAL
OF THE
ROYAL MICROSCOPICAL SOCIETY.
OCTOBER 1884.
TRANSACTIONS OF THE SOCIETY.
XVI.— Researches on the Structure of the Cell-walls of Diatoms.*
( Continued.)
By Dr. J. H. L. Fréaer.
at
(Read 12th December, 1883.)
Puates IX., X., anp XI.
5. Triceratiwn.
Tue old attempts to explain the sculpture of this group may be
assed over, also Prof. A. Weiss’s work of 1871 (28), since we
ve a very good paper by O. Miiller on Tvriceratium favus Ehrenb.
(15), which elucidates the entire sculpture of the valve in a most
satisfactory manner. I might therefore omit my investigation of
T. favus, the only species I examined, the more so as I have
generally only to confirm Miiller’s results. As, however, Tricera-
tium is taken as the type for diatom sculpture generally, and
because in minor points I arrived at somewhat different results, I
prefer not to suppress my investigations which were made from
sections (serial preparations) and casts. The material was presented
to me by Herr Moller, of Wedel.
The production of sections perpendicular to the surface of the
membrane is a comparatively easy task. The large triangle can be
readily seen in the gum, and the knife guided accordingly. Series
of 15-20 sections can be made without difficulty.
We have, as Miiller correctly describes, a thin basal membrane
adjoining the cell-lumen, and apparently quite smooth. © On the
outer surface is a system of ordinary network mostly representing
hexagonal spaces, which are vertical chamber-walls. Above, these
lines extend to almost horizontal walls, leaving, however, for each
of these chambers a large round central opening. ach of the
* The original paper is written in German, and has been translated by Mr,
‘J. Mayall, jun.
Ser, 2.—Vor. 1V. 2¥
666 Transactions of the Society.
hexagonal cells observed in the surface view is therefore « chamber
in the shape of an hexagonal prism; only the base of the same,
the outer surface, is not complete, but has the well-known and
often-described circular opening. On the vertical walls—namely,
the side faces of the prisms—in the corners of every third chamber
isa spine. If the thicknesses of these fine membranes are to be
measured, very choice sections must be taken. The basal mem-
brane has a very fine sculpture as illustrated by Weiss, but much
better and more accurately given by Miller. It consists of a
system of fine dots, radiating in lines from the central space of the
entire valve, and of which 60-80 are contained in an hexagonal
cell. Only on the finest sections with the highest power one
catches a glimpse of these points. I cannot say that the line would
thus be seen distinctly beaded ; and equally invisible are the points
adhering at the inner side only of the basal membrane, as Miller
represents it in transverse section (his fig. 11). Possibly these are
also chamber-like cavities, as with Plewrosigma. The definition
will be very difficult, but possibly casts will help us hereafter.
We have still to consider the margin of the valve and the three
horn-like protuberances. Miiller has spoken of these explicitly, but
I find some variations. With regard to configuration of the margin,
Miller gives correctly (his fig. 9) the view of the surface of the
marginal line. The transverse section (his fig. 11 d) represents
this line too much bent inwards. I have therefore given a diagram,
plate IX. fig. 21, of one of my transverse sections. The line is nearly
vertical to the membrane surface and is slightly broader at the top,
not pointed. The three protuberances at the three corners of the
triangle have been correctly rendered by Miller ; but everybody who
has not seen them in sections will find it difficult to realize them
in his figs. 6 and 7, because they exhibit too much of other detail
and shadow. For this reason I give the diagram of a true vertical
section of such a protuberance, fig. 22. According to Miiller,
these protuberances might possibly be open at the point, for which
I have not found the slightest justification. Nor is his cited ex-
ample of Hupodiseus a proof, in my estimation, because I see the
points in this group also closed.
The method of collodion casts confirms in general the results
obtained by the section method. The collodion enters through the
outer larger opening into the chamber, and leaves on the surface of
the dry cast a somewhat round mass which has very little likeness
to the beautiful regular prism of the chamber. On closer examina-
tion one distinguishes these spines in the cast as distinct depres-
sions in the corners between the masses. The cast of the inner
side of a valve is perfectly smooth. I could not succeed in obtaining
a cast of the delicate porous structure, either because it does not
exist or because the collodion used showed reticulation in hardening.
The Structure of Diatoms. By Dr. J. H. L. Flogel. 667
6. Coscinodiscus.
Of this species I have examined four varieties. I collected the
material myself on the Norwegian coast, and another portion was
from the ‘ Pomerania’ expedition (9).
§ 1. Coscinodiscus radiatus Khrenb.—This species gave the
best results, because the chambers are of considerable size, and I
had a sufficient quantity of them. Among the specimens obtained
with the knife one is especially interesting, because it was ob-
tained during fission. This is represented in fig. 31. I photo-
graphed a particularly successful section as a type-image. This
section is very good, but for the study of the sculpture a little too
thick ; for this reason I have delineated in fig. 23 the marginal
portion of an adjoining fine section under very high magnification.
From both images the sculpture of this species may be deduced as
follows :—The general form of C. radiatus is a very thin disk like
a coin; both faces are circular and display the pretty delicate
areole. Vertical sections through the disk give everywhere the
same image, the central one included. The cell-wall of these disks
consists of a very thin basal membrane, having on the outside
very delicate but prominent network. This network is enlarged
and thickened at the end, and so much enlarged that the lines
almost coalesce. In inferior sections one sees a continuous outline,
which is divided from the inner membrane by bars, but in very
good sections the lines have the shape of a T. In consequence
the network forms prismatic chambers, mostly hexagonal, but also
five-sided and four-sided, which without doubt must have an open-
ing from the outside, even if it be very small. In the surface view
I did not observe this opening until after my attention had been
drawn to it by the sections. It is seen with balsamed prepara-
tions like a small nodule, having 1/4 to 1/3 of the diameter of an
areola, and in superficial examination it may easily be mistaken
for the focal image of a chamber. To decide this point search
must be made above the acute portion of the chamber-walls.
The large number I examined of good sections which all agree
when thin enough, and show no continuous outline, prove defi-
nitely the existence of a small opening. The opening, in proportion
to the size of the chamber, is smaller than the circular opening
of the Triceratium chamber, as may be seen from the diameter
of the chamber-walls, which have a somewhat different shape from
Triceratium. Otherwise they are both very similar, but Coseino-
discus has no spines ; the outer surface is therefore smooth. The
height of the chamber is equal to its breadth (8-3-2). To-
wards the edge of the disk both dimensions decrease. The girdle-
band is seen in most of the sections; it is without sculpture.
Regarding its connection with the two inner newly formed cell-
me
668 Transactions of the Soctety.
wails several results were obtained with the sections. These
two new disks have the same sculpture as the two of the outer
valves, except that all outlines are much finer, and the chambers
are also not exactly of the same definite height. One observes that
the chamber-walls in the two young disks sometimes touch each
other, sometimes not. The manner in which all these parts are
connected with one another is very peculiar. I must here refer
to what I say further on about Achnanthes. With Coscinodiscus
there is no doubt that at least the one of the two newly formed
cells is completely closed outwards. The basal membrane of the
one outer valve goes continuously in equidistant curves into the
basal membrane of the corresponding inner valve; at the bend
a few delicate lines are seen which are the sections of the walls of
the considerably reduced marginal chambers. Out of this portion
the new girdle-band must be developed, as hitherto it has not been
detected. One observes in the other newly formed cell (the lower
one in the fig.) existing in all central sections a break, which the
membrane of the new valve makes at the bend, and this gives the
appearance as if the basal membrane of the old valve was con-
tinued here directly in the inclosed girdle-band, which is probably
the case; but one also observes here a break. Nevertheless I
believe that this second cell is closed at the bend of the membrane,
a conviction to be gained only by very careful study of the entire
section series. Future investigators who will work with patience
have an inexhaustible field before them; they will have to turn
their attention specially to the gradual development of the chamber-
walls and determine whether, for example, as Miiller indicates for
Triceratium, network arises from a basal membrane at first
smooth, or whether it is more probable that at first hollows are
developed in the membrane which afterwards become chambers
open at the top. It is interesting to see im this fission specimen
how, during the process of division, the lumen of both cells was
reduced almost to nothing, and very nearly the entire inner space
of the former mother-cell was filled up with the substance of the
two new walls. A coalescing of the two disks during the imbed-
ding in gum cannot be entertained, inasmuch as they would show
cracks at the edge, as old valves are unusually brittle. If we com-
pare with this an ordinary undivided specimen, from one of which
T have given a nearly median section out of the marginal portion,
fig. 24, the difference is at once apparent. In other respects such
a section displays very little variation from the above representa-
tion. The first section through the same specimen, which shows
the girdle-band of the surface and the minute chambers in the
convex edge, is given in fig. 25. I could not obtain collodion
casts of any service, nor could I succeed in fixing permanently
colouring matters in the spaces of the chambers. If the latter
The Structure of Diatoms. By Dr. J. H. L. Flogel. 669
could be accomplished with not wholly soluble but only suspended
colours a further clear proof would be furnished of the existence
of the openings of the chambers. Fossil specimens of Coscino-
discus radiatus from marl slate from Oran, for which I have to
thank Prof. Dippel, appear in their section-images quite in harmony
with the above. As a matter of course here is no longer cellulose,
and the valves and the girdle-bands are isolated. In the surface-
image the opening to the chamber is a little larger than with the
other specimens, which may be attributed to the loss of the cellulose.
Putting the outer surface (for instance, line 1, fig. 23) under a
high power we see these openings as delineated in fig. 26. By
slightly raising the slide so that line 2 is seen, the inner ring dis-
appears and distinct chamber-walls are seen, fig. 27. One esti-
mates the thickness of these walls in the surface-image too high, a
circumstance connected either with the magnification of the outer
marginal thickening of these walls, or which must be explained by
the reflection of the light from the walls.*
In a few specimens, not far from the edge, I observe unusually
large chamber-walls, fig. 28; the cavity is apparently quite
spherical, and only at some distance off does it take the prismatic
form. It seems to me quite unimaginable that the membrane should
have raised itself as an annular wall until quite above or nearly
so, and then have closed itself again over such a cavity (the pointed
shaped opening seems really sometimes to be wanting altogether) ;
and for this second reason in support of my former conjecture—
according to which the cavities develop and enlarge themselves in
the substance of the walls, and in this case open by the resorption
of the girdle—I give preference to my explanation rather than to
Miller’s.
§ 2. C. Oculus iridis Ehrenb.—The works of Slack, Stephen-
son, and Morehouse relating to this species (25, 26, and 13), I know
only through Just’s ‘Jahresbericht.’ According to Pfitzer’s refer-
ence, Stephenson describes an outer layer of deep hexagonal cells
which are one anda half times as deep as broad, and which, judging
from the positive images which they give of outer objects, are either
open on both sides or closed by nearly plane membranes. The
latter becomes more probable through the appearance of small
depressions in the base of the cells, the edge of which is undulated.
The inner layer Stephenson describes as a thin hexagonal areola
* On this subject compare my work on Pleurosigma, p. 507, where the reflee-
tion appearances within vertical chamber walls are fully discussed. With a
stage having an opening covered by a glass plate which is slightly tilted
these experiments can be controlled. Since outwards of the edge-line of a wall
black always appears first and white within, it becomes evident that with small
dimensions an apparent thickening of such vertical membranes must always
reg because the eye naturally takes the middle of the black line as the
imit.
670 Transactions of the Society.
plate having a spherical opening in the centre of each hexagon.
Slack asserts he has seen real depressions and a real projecting
network, both composed of small spherules. Morehouse sees duplex
valves, the inner of which has spherical openings, the edges
representing the thickest parts of the valve; the hexagonal net-
work of the outer valve lies in the depressions between those edges.
Across the mesh of the network extends a thin siliceous film with
most delicate anastomosing network, having its weakest point in
the centre. All sorts of things may be observed on this object if
one remains satisfied with a mere examination of the surface. The
nearest approach to the real state of affairs was made in 1880 by
Prinz (21). His figs. 7 and 8 represent tolerably well the vertical
chamber-walls, although by the method applied (the experiments
were made with thin rock sections) the real details would be difficult
to make out. This species viewed on the surface is to be dis-
tinguished by the large areola in the centre of the disk; the section
shows that the entire cell has no longer the form of a coin, but, in
consequence of the slight curving of the disk, is like a bi-convex
lens. The areole are slightly smaller than those of C. radiatus.
My somewhat numerous sections through one specimen are very
similar to those of C. radiatus, but I find nowhere a definite clue
for the existence of an outer opening. In fig. 29 a small portion
of a vertical section is given to the right, as observed with most of
the sections; on the left are seen small portions in the edge of fine
slightly injured sections. Here I am in doubt whether the
T-shaped figures may not be produced by the splitting of the very
fine outer membranes which are in the girdle; if everything in the
gum is uninjured one sees the membrane extending evenly across
the supports without indication of holes. It is curious that with
this species very often an air-bubble remains behind in the chambers
which hardly ever occurs with C. radiatus and Pinnularia, and
this might suggest that the fluid gum does not enter through
openings but in the more difficult endosmotic process. It is
unnecessary to deal more in detail with the statements of Stephen-
son and Slack. The former has apparently arrived at his view
through examining a specimen in process of fission.
§ 3. C. centralis Ehrenb.—This is a very large species, of
1/3 mm. in diameter, strongly convex, having in the centre a few
large areole. I have before me a number of sections through a
valve which had unusually coarse markings, thus differing but
slightly from C. radiatus. Fig. 30 is a portion of one of the best
sections, and shows the chambers with the T-shaped sections of the
walls, suggesting arches; the surface view is like C. radiatus.
Here also no opening can be detected in the finest edge-portions,
therefore I believe I am accurate in stating that this species has
completely closed chambers. One must not be led away by the
Lhe Structure of Diatoms. By Dr. J. H. L. Fligel. 671
marginal shadows which give the above strongly thickened T lines.
A close examination confirms the existence of a very fine line
between them. Hence we have here two distinct membranes con-
nected by a system of mesh-like walls. The walls commence at the
inner membrane very thin, and gradually become thicker as they
approach the outer membrane, so that they appear wedge-like in
the section. Similarly the adhesion point at the outer membrane
is thickened, and this thickening gradually diminishes over the
centre of the chamber. ‘he outer surface of the outer membrane
is uncommonly even, so much so, that in a dry condition the valve
reflects light as strongly as a mirror. This fact alone cannot be
reconciled with the idea of openings (C. radiatus does not reflect
as a mirror), anyhow the openings could not be estimated at more
than 1/8 or 1/10 of the chamber diameter in order not to interfere
with the smoothness of the membrane. Collodion casts would be
very desirable in the investigation of this species. The dots of the
areole in the surface view, formerly described and figured by me
(9, p. 86, fig. 6), cannot be seen in the sections.
4. C. concinnus W. Smith.—This species is much larger and
more delicately enveloped than the former, about 0°5 mm. in
diameter and equally convex. The section of a valve of a not very
large but very finely marked specimen, fig. 31, shows the familiar
image of chambers closed on all sides, such as I demonstrated by
my Pleurosigma investigations, except that with this Coscinodiseus
they are considerably larger (about 1 yw). The valve reflects light
strongly. For the surface view I refer to my former notices and
figs. (9, p. 86, fig. 5). After the investigation of these four
varieties I believe that in the species of Coscinodiseus we have before
us the gradual transition from the Triceratium type to the Pleuro-
sigma type, inasmuch as the small outer opening of the chamber
which is still seen in a few varieties, totally disappears in others.
7. Isthmia.
It is not at all difficult to cut this giant amongst the diatoms,
but it is very difficult to obtain sections of the requisite degree of
fineness. The cell-wall is everywhere of unusual delicacy. After
examining some forty-five sections I am enabled to give the follow-
ing description of the cell-wall :—
There is a difference between that portion of the frustule which
corresponds to the valves, viz. the sloping ends of the rhomboidal
cell, and the middle portion, which is to be regarded as the girdle-
band and under which the division takes place. This difference is
marked outwards by a strong expression of the areole in the end
portions in contrast to the delicate markings of small cells in the
girdle. With the sections one must always endeavour to determine
672 Transactions of the Society. -
to which part the portion belongs which is under examination. In
order not to err on this point | have kept to the pointed ends in ©
the investigation of the valves, and which exhibit in the section
comparatively very small rings. Photograph 19 illustrates a
section through two frustules and through one connecting end
being the isthmus proper. The small ring, without doubt the
valve, shows on the inner side distinct projections, that is to say,
wall-thicknesses apparently vanishing like network produce the
cell-ficure in the surface view. The membrane at the non-
thickened end, that is to say, at the lumen of the pseudo-cells,
is of extreme thinness. The immediately preceding much finer
section corroborates still more what I say. ‘The thickness of the
wall is about 0°3 w, and in the net projections 1:2 wu, we thus
obtain an image of simple inner cell-envelope thickenings in a
manner leaving nothing to be desired, and which has not the
slightest similarity to Tvriceratium. The cell-wall of the middle
girdle differs inasmuch as the thickening lines producing the
markings are undoubtedly on the outer side. The wall-thickness
is so extraordinarily small that with a magnification of 1000 it
appears only as a mere line. The net-lines are also very flat,
about 0°7 w in height. With reference to the girdle-band
one can speak with full conviction of a surface-sculpture, whilst
with the valves one must say inner surface-sculpture. Here
may be added that Isthmia has a large cell-nucleus lying in the
inner granular protoplasm, and which was touched by me several
times in my sections. It is a spherical transparent vesicle of 16
diameter, having a spherical nucleolus of 4:5 w in diameter. The
result obtained from surface views of dry imbedded Isthmiz does
not at all agree with that obtained with the transverse section
images; the thickening lines appear like strong refracting masses,
and were looked upon as such by the earliest investigators
(Ehrenberg, Kiitzing, and others). It was not at all to be expected
from an @ priori examination that the sculpture of this species
would appear so totally different from Triceratiwm. I shall not be
expected to enter further into the researches of Slack (25), according
to whom the membrane consists of small spheres.
8. Achnanthes.
If an obstinate defender of the opinion that diatom sculpture
consists of inner cell-wall thickenings, wishes to secure an object
substantiating his view, I can very strongly recommend to him the
large forms of Achnanthes. After having occupied myself inland
for years with fresh-water diatoms, on meeting with the marine
Achnanthes I believed I had found the long-searched-for proof.
Each surface view under a good Microscope shows clearly the
The Structure of Diatoms. By Dr. J. H. L. Flogel. 673
projection of lines on the inner side of the membrane, whilst the
outer side is perfectly smooth. It can be seen more distinctly in
sections, but in proceeding we shall soon have to admit that a part
of what we stated has to be reconsidered. The following relates
only to Achnanthes brevipes Ag.*
§ 1. We have to distinguish three sorts of markings in
Achnanthes. This diatom has an unsymmetrical shape at the
division-plane, so that only the two middle sections vertical to this
plane give symmetrical halves. Therefore we get:—(1) A dorsal
valve characterized by greater convexity; it has a mid-rib without
nodule running evenly from one end to the other; close to it
run the smooth transverse lines, the interspaces of which are wider
than those of the ventral valve; between every pair of transverse
lines are seen in most instances three rows of dots, sometimes only
two. (2) A ventral valve, characterized by a thick depression in
the middle; it has a mid-rib with even striz on both sides, in the
centre a large nodule which at right angles to the mid-rib extends to
the edge, thereby producing, the same as with Stawroneis, the
image of a cross. ‘The transverse lines are finer than in the dorsal
valve; between each pair, as a rule, one row of dots, sometimes
two. (3) The girdle-band, always with delicate striz vertical to
the division-plane, which however is subject to variations as we
shall presently see. The figs. 33, 37, 38, and 39, plate X., of
A. brevipes sufficiently illustrate this description.
Two good serial sections are obtained, running vertical to the
division-plane and to the two mid-ribs (in fig. 33 this is delineated
by lines 1-3); the third series I made approximately parallel to
the division-plane. My attempts in the third direction of space
(the horizontal) failed. From one of the two former series,
numbering twenty-three sections, I have delineated three, viz. 1, 5,
and 15, figs. 40-2, plate XI. No.1 is a marginal cut; 23 has
nearly the same appearance. No. 15 cannot be far from the middle,
because among the succeeding numbers are a few of too great
thickness.
Examining first the general form, we see from the sections
in which all three conform, that the ventral valve is depressed,
trough-like, along the mid-rib, whilst the dorsal valve appears half-
cylindrical, that is to say, rounded off convexly. By this feature
* The difference between A. brevipes and longipes Ag. is often very great.
A. longipes commences with a short pedicle ; the pointing or rounding of the valves
is somewhat variable, and the distance between the striw is not always definite.
From the stria distances and the length of the pedicle, I believe I have deter-
mined the specimens investigated to be A. brevipes, but they might belong to
A. longipes. The specimen figured by Pfitzer as A. brevipes (19, pl. vi. fig. 15 s)
I should rather suppose to be A. ventricosa Ktz.; anyhow, this variety is not
the one investigated by me under the name of A, brevipes, I have found
A. ventricosa on the sea-shore near Sylt, but could not make use of it in the
present investigation (vide 5, p. 737).
674 Transactions of the Society.
we are able to distinguish either valve even with imperfect sections.
The convexity of the dorsal valve fits nearly into the trough of the
ventral valve, so that they touch each other when of large size.
The section-bundle consisted of three frustules, of which the lowest
was probably near the period of its second division, whilst the other
two had only recently emerged, therefore the lowest, compared with
the others, is probably backward in development. The girdle-band
comprises only the limit-line between the lowest and middle frustule.
With reference to the fine sculpture, mention must be made of a
portion of membrane hitherto unobserved, and which could not
have been well detected without transverse sections. This is the
projection on the edge of each valve, that is to say, at the limit
between valve and girdle-band, a spine turning far inwards as
shown in the figs. (r /), and is found fourfold in each frustule. All
sections of the two series prove clearly these four projections; they
can only be the expression of a projecting line running along the
edge towards the inner space of the cell, I will call it edge-line,
which with the usual division of the frustule plays a prominent
part as we shall see. With low powers one sees only the four
small spines; applying the highest power one observes that the
larger spines, at any rate, are hook-shaped towards the valve-cavity,
fig. 43; it may actually become a hook, fig.46. ‘The end-valves,
being the oldest in the row, have the largest hooks and the strongest
edge-line. In the youngest valves one sees the partially developed —
hooks, sometimes hardly nodule-shaped, fig. 44.
The largest hooks penetrate 2 m into the cavity of the cell.
After having discovered the marginal lines in the sections it became
easy to trace them again in the surface view; they are particularly
well seen in balsam preparations (in consequence of the weaker
refraction of the walls). The older investigators, for instance,
Kiitzing (plate 20, [X., 1) and Ehrenberg, figure distinct dark
marginal lines ending with a nodule. The transversely cut marginal
line is in section far more conspicuous than the mid-ribs; in most
instances one sees the mid-ribs as round nodules standing off the
membrane ; occasionally they may be seen somewhat more distinctly.
Altogether the dimensions are very small, and only in the most
favourable instances can one determine that they project inwards
and not outwards. The valve surfaces are always seen in good
sections as distinct rows of dots, pearl-like, and this is the expression
of the fine dots of which I spoke above. These pearls I declare
to be, according to the best and most reliable sections, chambers
closed on all sides situated within the membrane. ‘The direction of
the cuts in the series in question being parallel with the actual
transverse striz, one can hardly expect to discover anything about
the condition of the latter. But if the section is very thin, one
sees on the inner side of the pearl row a fine straight line depressed
The Structure of Diatoms. By Dr. J. H. L. Flégel. 675
at the mid-rib, fig. 45, so that at the side of it are two thin
membrane-strie free from dots, such as we demonstrated in the
surface-image. ‘This fine line I consider to be the limit of the
inward projecting transverse striz, and also of the one touched
by the section ; for if it is thicker and comprises two transverse
strie, it will be looked for in vain in this image, because the
interference at the margin then becomes so strong that we can give to
the line any interpretation we please. The central nodules and their
expansion are not met with with certainty in either series ; unfor-
tunately they seem to have broken off at the touch of the knife.
The girdle-band in old valves has always a distinct row of coarse
strie ; in the surface-section, fig. 40, this is magnificently brought
out. These strize are about half as fine as the transverse stric of
the ventral valve. In the younger part of an old valve, or in a
young valve, the striz on the girdle-band are very indistinct. In
the transverse sections, inasmuch as the sections are in the direction
of these striz, nothing can be seen ; one observes no differentiation
whatever in this membrane except that sometimes irregularly a dot
appears on the inner side, which may indicate the delicate lines
running parallel to the marginal lines. The whole matter is to me
doubtful. I cannot explain the extremely fine structureless section
occurring at the margin of the surface section 1. Since the girdle-
band has no such non-striated portions in the surface view, it may
possibly be an outer substance hardened by the alcohol.
The serial sections which were made in a direction 90° from
the preceding (22 in number) cut through the surface from first
to last; but shortly after the first and shortly before the last, as a
glance at fig. 33 discloses, the transverse lines of the strongly
porous valves must, at the point where the two sides run parallel,
haye been struck exactly vertical to their direction. This, as a
matter of course, occurs likewise with several valves situated between
the two ends. Further, the girdle-band is seen in several sections,
and is cut vertically to its strie. The most suitable sections
through the part of the dorsal valve under examination, as repre-
sented in fig. 48, show that the transverse lines, as we learnt from
the surface view owe their origin to the delicate but distinctly
raised thickening lines on the inner side of the membrane. These
fine lines are about 0°9 w high, the membrane itself is 0°5 wu thick.
In examining the sections near to the last one, one detects the
fact not quite so distinctly in those which are unquestionably
taken through the ventral valve, but I have obtained with a well-
regulated position of one section an unequivocal image, fig. 47.
Between the transverse striz lies the chamber, seen only with very
fine sections, fig. 50. As a matter of course, the valve-section is
in places entirely surrounded by the adjoining girdle-band section.
The girdle-band can always be easily distinguished in these sections
676 Transactions of the Society.
by its peculiar regular fine pearl-like sculpture, figs. 45 and 52.
Now, what are these pearl rows? I believe they must be inter-
preted similarly to the sections of the Flensburg Plewrosigma
described by me (6, pp. 475-8), hence, in this case, probably a long,
extended, cylindrical chamber within the membrane. The apparent
projection on both sides of the surface must be an optical effect.
Clearness in these details with the extreme delicacy of the object
is hardly to be expected. The central nodule of the ventral valve
is a strong inward-projecting thickening, without any other dis-
tinction except that from every side it sends off a thinner line in
the transverse direction to the edge of the valve.
§ 2. With this we conclude our examination of sections in
general. I believe I have thrown some new light on the com-
plicated structural details of the species Achnanthes, although I
admit that much remains to be done. With the ample material at
hand it became interesting, apart from the above results, to make
the attempt to discover the development-processes which take place
in the gradual formation of these sculptures during ordinary
fission. Now that we know more exactly the connection of the
girdle-band with the valves, the former, not being structureless like
most of the fresh-water diatoms, will probably furnish data for
further elucidation of these hitherto obscure problems. In aid of
further research we should algo avail ourselves of simple surface-
views as well ag the examination of numerous freshly imbedded
and well-preserved specimens in balsam, because with the help of
transverse images the appearances can be correctly explained. I
do not hesitate to add here the observations which I have made
with a larger number of balsam specimens of Achnanthes. brevipes
even at the risk of engaging in controversy.
Taking a recently divided specimen, such as is shown in
fig. 83, and examining it with reference to the formation of the
girdle-band, one finds that between the two valves, viz. between
the one older and the one younger, there is no space. We observe
the marginal line, and close to this extends the young valve. If we
keep well in mind the image of the marginal line of another fuller
grown specimen, we shall be easily convinced that the younger
specimen has only one single line. Fig. 33 shows the frustule at
the edge where the young valves have only recently obtained the
necessary solidity to enable them to withstand the influence of
contracting fluids (I might have started from earlier stages, but my
objects not hardened with osmium show all sorts of bendings of the
young valves which I attribute to the modus operandi). Adjust-
ing the left cell as the optical middle section one sees the edge-line
. of the old dorsal valve like projecting nodules: close adjacent 1s a
smaller nodule which can be nothing else than the commencement
of formation of the marginal line of the younger ventral valve. On
The Structure of Diatoms. By Dr. J. H. L. Flégel. 77
the surface of the frustule such a second line cannot yet be traced
at all; on the contrary the transverse striz of both valves run to
the apparently common marginal line. This companion cell on
the right is in this respect slightly more developed, especially at
the one end (the lower in the figure). Not only is the small
nodule more distinct in the middle section, but it is also more
distant from the larger, and on the surface one can clearly see two
marginal lines not quite parallel. Fig. 34 gives the line of the
optical middle section again, but more highly magnified. Turning
now to another still younger specimen, fig. 35, we observe the two
marginal lines slightly further apart. The divergence of the lines
continues until the cell obtains the requisite breadth to divide anew,
fig. 37. The question arises with this divergence, what becomes of
the girdle-band and how is a new one formed? With regard to the
old, one sees clearly the edges are extending over the other, of course
mostly only with an immersion objective, and it would easily be
overlooked if we did not know where to search for it from Pfitzer’s
pioneer work. With regard to the processes accompanying the
formation and development of a new girdle-band we find but little
information in Pfitzer (19, p. 56). He states that the girdle-band
in Pinnularia is formed unusually late, only after the new valves
are complete, and then where it adheres to the valve; that it ig
seen almost at first in its definite thickness reaching slowly to its
normal breadth. According to Pfitzer (19, p. 9) the girdle-band
has an outer edge in organic connection with the valve, and an
inner free edge touching the other ring but not grown together.
With Achnanthes—and here the non-existing marginal line
of Pinnularia renders capital service—we can establish with all
desirable certainty that the girdle originates in these lines. One
has only to go backwards in the various stages of development in
order to establish the fact. At the point where the distance
between the old and the young line can be well observed, one sees
distinctly with an oblique position, fig. 36, that the cell-wall
between the two lines is of double thickness, hence at that point
there must be already a younger girdle-band. Of course, with the
extreme thinness of the two bands the duplicature cannot be
observed directly ; the line expressing one cleft extends, as far as I
see, up to the young marginal line, fig. 36,77. But since this
was attached originally to the older line, the girdle-band without
doubt is so far a double membrane, as it has already been rendered
probable by its thickness. Following up backwards this very thin
narrow girdle-band, fig. 33, on the left, we find here its origin
in the depression of the marginal line. We further deduce
from these Achnanthes images that, according to my exami-
nation, it is clearly evident the girdle-band from its commencement
is attached to the cell, since it fills up entirely the inner space
678 Transactions of the Society.
between the two marginal lines. From this I deduce further:
there is no free edge of the girdle-band, such as Pfitzer has
described with Pinnularia, anyhow not so long as the cell is only
of moderate breadth ; both edges are grown to it.*
When this connection ceases must be discovered by future
researches. But there can be no doubt that at some time or other
a process of forcible separation must take place. This separation
always occurs in a segment of the old marginal line. We are
therefore justified in stating that at that spot the new formation of
cellulose takes place, whilst further on towards the new line, the
membrane is already solidified and capable of resistance. Some
proof of the correctness of this view is found in the development
of a strong margin near this spot; the lines become weaker the
further one goes from this margin. In the cell, shortly before divi-
sion, fig. 37, the tearing-off of the young girdle-band has taken
place. This looks like the signal for a new division; at the
moment of tearing off, the compressed contents in the rigid cell-
envelope become suddenly free, at least in one direction, and can
hence extend, inasmuch as the girdle-bands are drawn out like
telescope-tubes. If these views are correct they lead us to the
conviction that the older outer girdle-band is a safety-sheath for the
inner younger girdle-band ; it prevents injuries to the latter whilst
partially in a non-silicified condition; it protects with its older
strong portion the younger recently formed annular portion of the
inner band. From this may be deduced that Achnanthes is in
many respects similar to the growth of the cell-envelope of
Cidogonium (may we say to the large marine Conferve ?).t
We must now cast a glance again at the sections. None of
the uninjured (fig. 43) confirm these assertions; one observes from
marginal line to marginal linea fine simple membrane, consequently
without doubt twofold. But only when a section is injured and
its substance has been slightly removed by the knife during the
operation of cutting is the real state of affairs brought to view. In
fig. 44, otherwise very similar to fig. 43, we see a portion of such
a section in which the young girdle-band can be traced; a de-
pression being nowhere observable in the space up to the old
marginal line, the girdle-band must have grown there. We also
find in such slightly injured sections clear proof that it easily tears
off at the old marginal line. If I wanted to convince the reader of
* I might mention en passant the physiological objection against the non-con-
nection of the two valves, that the water must find access to the inner space,
however narrow, and would thus come into direct contact with the protoplasm,
through which the latter, according to all established experience, would swell
and possibly effect a separation of the halves.
_t Whether the enlargement of the cell-envelope of Rhabdonema adriaticum
(wide Nageli and Schwendener, 17, p. 544) hasits cause in a similar law seems to
me to require fresh investigation.
The Structure of Diatoms. By Dr. J. H. L. Fligel. 679
the accuracy of these views which I acquired in the examination of
the sections, I should have been obliged to photograph an entire
series.
The question whether the diatoms become smaller through
repeated division can be well elucidated with Achnanthes, espe-
cially if one is possessed of richer material than I have, and by
examining and comparing the measurements. In doing this we
should start with the marginal lines of very young specimens.
What I have seen in my examination of Achnanthes preparations
confirms the results obtained by Braun and others, especially
Pfitzer (19, pp. 20-8, 100-102) with Himantidium. I confess I
see several specimens in which the younger valve is shorter than
the older; but I have also found some where the length is greater
than in the older, which may possibly be caused by the girdle-band
having enlarged itself at the edge. The normal condition appears
to me to be an exact equality of both valve-lencths. On the one
hand this follows from the manner above described in which the
first traces of the young marginal line are developed, fig. 34, and
where with the best methods of measurement no difference will be
found. On the other hand one sees, by careful examination of such
young cells, that the older girdle-band is always slightly raised,
that is to say, about as much as its thickness 0°4-0°5 w; to this
extent it grows over the old valve. Next, one can often see with
Achnanthes longer cell-rows in connection, all of equal size. This
has been minutely discussed by Pfitzer. We have lastly in
Achnanthes in so far a very favourable object, that the valves are
not similar as with Pinnularia and Himantidium, but on the
contrary are very different, and no definite judgment can be arrived
at with regard to age and number of generation. Now, if I
examine a few good rows composed of eight frustules, where for
example the lowest and oldest ventral valve is together with the
youngest dorsal valve coming out of the third division, then I find
no difference in size between the grandfather and the great-grand-
daughter, although the threefold thickness of the girdle-band,
always a good measurable size, would have to be deducted with
the latter if Pfitzer’s theory were in this instance correct. How-
ever, who will guarantee that we have here to do with the grandfather
and the great-granddaughter? ‘The hundredth division may already
have taken place, since it is known that in time only individuals
connected by mucus are thrown off. All considered, I am of opinion
that Achnanthes contradicts rather than confirms Pfitzer’s theory,
and that the supposed corrective of the cell diminution, namely,
the formation of auxospores, may have other purposes. The decision
of this question must be left to future investigators. Whether the
corner of the ventral valve developing the longer or shorter spine
by which this diatom is fastened on other alge, is of different
680 ~ Transactions of the Society.
structure from the one at the other corner seems probable at the
first glance, but nothing definite on that point could be made out.
It seems to me that the spine is the outdrawn end of a general
gelatinous cover secreted by the entire valve-surface. The cell-
nucleus of Achnanthes, fig. 46, is a small spherical vesicle of 4 u
in diameter with nucleolus of 1 p.
9. Synedra.
With Achnanthes I have given numerous transverse sections of
Synedra Gallionit Khrenb., often and everywhere found in Kiel
harbour, fig. 53. Beyond its general form very little can be
deduced, especially as we are left m the dark as to how the in-
significant transverse strize are caused on the edges of the square.
Ill. Resuuts anp GENERAL REMARKS. ©
The detailed researches given in the preceding chapters shall
only be mentioned here in so far as they relate to the sculpture of
the cell-envelope, whilst I must refer to the above for the facts in
connection with the girdle-bands, fission, &c. These researches
comprise in all, seventeen varieties of diatoms (Pinnularia major,
viridis, and Crabro; Navicula Lyra; Plewrosigma balticum,
angulatum, Scalprum ; Surirella biseriata; Triceratium Favus ;
Coscinodiscus radiatus, oculus iridis, centralis, and concinnus ;
Isthmia enervis; Hupodiscus Argus; Achnanthes brevipes, and
Synedra Gallioni), which have all been examined by the section-
method, also to some extent by other methods. The result is that
the marking of the diatom coatings has its origin in various forms
of the wall-thickness and in the cavity formation within the
membrane. The results can be grouped as follows :—
The marking is caused :—
(1) by the sharply projecting wall-thicknesses.
a, on the inner surface of the membrane:
Achnanthes = transverse strize, Isthmia = valves,
probably also Grammatophora, Epithemia, and
others.
b, on the outer surface of the membrane:
Isthmia = girdle-band.
(2) by developed chambers within the membrane, and
a, with distinctly observable openings.
* Which are on the outer surface of the cell, whilst they
are closed inwards (in a certain degree transition from
type 1 b):
Triceratium, Coscinodiscus radiatus, and possibly a
few other varieties.
+ Weiss, 28, p.9; Miiller, 16.
The Structure of Diatoms. By Dr. J. H. L. Flégel. 681
** Which are situated on the inner surface of the membrane
where the chambers at the same time have the
enormous extent of almost half the breadth of a valve,
Pinnularia, and probably all single striated forms.
b, without distinct openings, but of considerable size.
* With quite smooth chamber-walls:
Coscinodiscus centralis, and others.
** With nodular thickened chamber-walls :
Eupodiseus.
c, closed on all sides, and extremely small, approaching the
limit of discrimination :
Plewrosiqgma, Navicula Lyra, Surirella, Achnanthes
(the finer marked variety), and probably most of
the finely dotted striated forms,
Having thus given proof of the existence of various types as
the cause of the surface-image, the necessity arises of refuting those
investigators who constantly talk of a diatom sculpture in general,
of surface-sculptures, of furrows, cup-like depressions, hemispherical-
shaped prominences, &c. In so far as this has not already been
done in my paper I now undertake the task.
Prof. Weiss propounded in 1871 (28) an entirely new view
of the sculpture of diatoms, which is formulated by him (pp. 15-6)
as follows: “ The markings of the various diatom species, however
different they may appear under low magnification, differ only
apparently ; under high magnification, and with a correct inter-
pretation of the sculpture, all diatoms are constructed on the
same principle, namely, they consist of more or less polygonal
cellules, the walls of which, with low magnification, produce and
condition the configuration of the so-called markings.” The inner
cavity he compares (p. 9, footnote) with the embryo-sac of the
higher plants. ‘The notion that the envelope consists of numerous
minute cells is so thoroughly erroneous that we need not quarrel
about it. ‘The attributes of a cell do not consist, aczording to our
present knowledge, in the wall alone which surrounds a cavity,
and it is impossible to look upon each cavity as a cell-lumen even
if it should have regular form. ‘he discovery of nuclei within
the so-called cells (p. 30) must be traced back to an error in the
examination ; they would never have escaped me in my manifold
staining processes. Nuclei which take up no colour I may say
do not exist. ‘The idea that all diatoms have a common sculpture,
I contradict most emphatically. I cannot at all comprehend how
Prof. Weiss, with his great knowledge of details, and with the
enormous quantity of material at his disposal, can have arrived at
such an opinion. We must, however, give Weiss the credit that
he was the first to demonstrate that the presence of cavities closed
Ser. 2.—Vou. IV. 22
“682 Transactions of the Society.
on all sides was the cause of the marking during the development of
the valve. Considering the criticisms Weiss’s work has experienced
through the erroneous theory of furrows, sculptures, &e., the credit
due to him must be kept prominently in view.
Of similar tendency are the works of Count Castracane, for
which I refer to Just’s Botan. Jahresb., 1873. It will be equally
unnecessary to enter upon their contents.
I have at various times in the course of this paper referred to
Prof. Pfitzer’s epoch-making work (19). I am obliged to speak
of it once more, because at the conclusion, speaking generally of
the cell-envelope of diatoms (p. 174), he reproaches me with having
in my Pleurosigma researches insufficiently estimated the possibility
that the connections between the two surfaces of the cell-wall are
distinguished from the interspaces by the stronger refractive power
due to the molecular constitution. Then he refers to the bast-cells
which have similar sculpture, and as worthy of notice he mentions
that with diatoms differences could not usually be due to water,
but to silica-contents. I do not know Pfitzer’s reason for this
statement ; I have fully explained (6, p. 474) that I have examined -
fresh specimens which had been boiled in nitric acid and in chlorate
of potash, and further (p. 485) that through continued boiling the
sculpture does not alter. In the latter case, surely nothing else
but silicic acid remains; then what does he mean by making a
difference by saying silica-contents? The transverse section of a
boiled valve shows exactly the same walls as previously. It
appears to me that my demonstration of closed cavities came to
Pfitzer’s notice at an inopportune moment, because in the same
journal he brought forward his furrow theory which, as we have
seen above, is wrong in every respect. Since Pinnularia seems to
be the only diatom examined by Pfitzer by the section method, in
order to discover its sculpture, he adopted it as the type of diatom
sculpture, and when, soon afterwards, Miller proved real outer
openings in Triceratium and tried to make useless corrections of
my work, Pfitzer evidently believed that I had fallen into error,
and that his so-called surface-sculpture was a property common to
all diatom frustules, Pleurostgma included. In proof of this, one
need only glance at Pfitzer’s subsequent writings. Let me only
draw attention to his latest (20), from which we might infer that
it expounded to some extent the latest views on the subject. But
about the structure of the cell-wall it contains nothing other
than Pfitzer’s furrow theory, and O. Miller's sculpture of
Triceratium.
Another paper which we have to discuss is by Prof. Abbe:
‘ Beitrage zur Theorie des Mikroskops.’ In this work (1, p. 450) it
is demonstrated “that all the finer sculpture of an object, of which
the elements are small and close enough to produce by their
The Structure of Diatoms. By Dr. J. H. L. Flégel. 683
proximity an observable diffraction phenomenon, are not imaged
geometrically in the Microscope, that is to say, not as if the homo-
focal emergent pencils of rays from the object represented it point
for point on one image-surface.” From this he draws the con-
clusion (p. 453)—“‘all attempts to determine the sculpture of the
finer diatom-valves by morphological interpretation of their micro-
scopical images seem founded on inadmissible premises. Whether
Pleurosigma angulatum has two or three systems of striz or
whether real striz are there at all, or whether the observed mark-
ings are caused by isolated elevations or isolated depressions no
Microscope can determine however perfect it may be or however
strong its magnifying power.” Further (p. 454)—“ that the same
condition of things exists very nearly for a great number of purely
organic images in histological work, can be learnt by the example
of striped muscular fibre. In good preparations the diffraction
phenomena can be easily observed, and their effects in the micro-
scopical image can be studied experimentally in the former-described
manner. The manifold differences in the character of the image
explain to some extent the disputes which have arisen between
different investigators on this point; but at the same time they
also establish the impossibility of stating anything definite about
their real organic composition in the sense of the attempts made
hitherto.”
I am not aware whether Professor Abbe still clings to these
views expressed in 1873, or whether he has since convinced himself
of their error. From his publications which I have since occa-
sionally seen, I believe he still holds to the former opinion. These
theses figure as principal results in a journal of eminence, which
must be read by everybody who wishes to keep an account of what
he sees in his Microscope. Therefore I consider a refutation of
these theses in this place a necessity.
Since the structure of muscular fibre and the differences
amongst histologists of that date are put forward as examples of
the correctness of the assertions, it may be well to bear in mind
that the greater number of histologists have not adopted in their
researches Prof. Abbe’s views; and that now-a-days the com-
plicated structure of the transversely striated muscle-fibre is nearly
established. ‘This is not only valid as regards the single layers
composing the fibre, but also for the double-refraction of certain
parts, of which Abbe also states (p. 453), it was futile to entertain
the idea. I will not here enter into the full details how, at the
commencement of the last decade, the confusion chiefly brought
about by Heppner’s wrong views about the muscle structure was
dispelled by my work ®) based on the examination of an unusually
favourable object, and I likewise demonstrated at the same time
that with the application of good hardening methods one can
222
684 Transactions of the Society.
obtain similar results on other objects, but less distinctly. Shortly
afterwards, the classical works of Engelmann, and more recently
of Merkel, whilst confirming the complicated muscle structure and
further by investigating the relations of the elementary particles
before and after the contraction, have closed the question for some
time to come.
If after this Prof. Abbe’s objection against muscle sculpture in
general is tacitly accepted as set aside, then, in view of the fact
that among the numerous diatom investigators hardly one has
seriously occupied himself with the structure of diatoms, it becomes
all the more difficult to controvert Abbe’s views since I am the
only one to whom falls the task of domg so. I must not forget,
however, that Dr. Altmann has every now and then vindicated my
views against Abbe.*
It would lead too far away from our subject if I were here to
enter on the merits of their differences; he who takes an interest:
therein should read Archiv fiir Anat., 1880, pp. 111 e¢ seg. In
our present discussion it is enough that all my results obtained
hitherto are in direct contradiction to Abbe. Any one desirous of
arriving at a definite opinion can inform himself by my diagrams
and photographs, or by repeating my experiments. Suppose the
student in microscopy investigates the sculpture of an object which
is unknown to him, limiting himself to the surface-view only, say,
for instance, the Plewrostgma valve, it is certain that he will be
unable to solve various doubts, and in this I quite agree with
Prof. Abbe; he will not be able to decide whether certain lines
are raised or depressed, whether they are situated inside or outside ;
on this subject microscopical literature records the most unfruitful
squabbles. But if the investigator examines the object by sections
and makes casts of the surface, and makes use of the staining
processes, &ec., and finds, for example, exactly at the place of a
previously doubtful line a projection, then it becomes immaterial to
him whether the Microscope deceives us in the surface-view and
gives images which do not correspond to reality. If the Micro-
scope deceives us in one case, then it also does so in others. The
change in the methods of investigation puts us in the position to
find out the truth. As soon as the investigator takes the result
obtained by all his methods and compares it with the surface-
image, he will in most cases have answers to all his questions
without being obliged to enter into the depths of the diffraction
theory. I observed these maxims in my work on Pleurosigma
sculpture, and I hold to them at the present day.
‘'o this cannot be opposed the fact that one can obtain by
artificial means images like diatom markings, and such diffraction-
* Personally I do not know Dr. Altmann, therefore I take this opportunity
to tender him my best thanks.
The Structure of Diatoms. By Dr. J. H. L. Flogel. 685
spectra as diatoms produce, and that therefore the microscopical
image is unreliable, and that for this reason no Microscope could
clear up the true facts. The first portion of the sentence I admit,
but the second I deny. That the half wave-length of light a
praxis indicates the limit beyond which in 1869 no Microscope
showed details, I had clearly demonstrated in my paper on the
optical appearances in diatoms (5); the great honour of having
proved theoretically the existence of this limit is due to Prof.
Abbe. I had surmised conclusions on the results of my diffraction
studies on the finer sculpture details, which | considered unreliable
after having successfully used the section method. Several other
objects furnish diffraction-spectra, although they are of totally
different sculpture which we cannot bring into parallel with the
diatoms: for instance, butterfly-scales,* and the skin of the
Ascarides whose diffraction phenomena have been studied by
Leuckart (12, vol. ii. p. 164). From the latter nobody can arrive at
definite conclusions on the sculpture; but it would be wrong to
assert that no Microscope in the world could elucidate it. Summing
up we may say: the diffraction phenomena suggest only the
existence of small particles of approximately equal size in layers,
but they convey nothing as to their form or arrangement. The
diffraction theory does not put a stop to the closer investigation of
the sculpture of muscles, diatoms, &c., and Abbe’s assertion that
we could never arrive at anything reliable about this sculpture is
unfounded and was practically refuted at the time he published it.
With this I believe to have given sufficient courage to all timid
students to continue their researches which otherwise would be
without prospect as long as Abbe’s opinion predominated.
The latest work by Prof. Strasburger (27, p. 143) treating of
the sculpture of the cell-wall of diatoms, mentions me with the very
unflattering sentence—“ F'légel believed he had found out that the
cell-wall contained chambers opening above as well as below.”
Then comes O. Miller who proves the opening with Triceratiwm.
I may expect that Prof. Strasburger after reading my present
work will alter his views considerably. Should I be disappointed
therein the way would be open to him to investigate the matter
himself personally, and I own that among all living botanists, I
consider him to be the most able to assist in solving the question.
Should he in such case also “believe” he has arrived at results
slightly different from mine, I would request him before presenting
the world with his results to try again a second and a third time
with different weather, with other sections, and with other physical
disposition personally, and then he will soon convince himself that
his former “ belief” was unbelief.
* About their finer sculpture I shall publish my investigations shortly in a
zoological journal.
686 Transactions of the Society.
If in the preceding pages one or other essay on this subject,
which has appeared during the last decade, has not been mentioned,
I would ask indulgence on account of the seclusion of my place of
residence; but I believe that no essential questions regarding the
subject have been overlooked.
With this I conclude my work, and for the present, on account
of otker studies, I take leave of a subject to which I owe many
pleasant hours of my lifetime. Whether the text-books of botany
will take notice of the fruits of my investigation, or whether they
will adhere to the old mistakes, may be left to the future. Up to
the present I have only seen one work, the excellent synopsis of
botany by Leunis, newly edited by Professor Frank, which gives a
true account of the newest standpoint in these questions.
Only by constant and persevering work can we expect further
progress; it cannot be done by the mere purchase of expensive
immersion objectives. He who will only judge from a usurped
high position; he who believes he can do something by setting up
diffraction theories; he who looks upon diatoms as aggregations of
erystals; he who believes he can decide upon all sculpture questions
by observation of the surface; he may keep to his own errors, but
he must not expect that I should answer his attacks which he has
based upon such means in order to find fault with my work, how-
ever learned may be his phraseology. Considering my positive
results, I must be excused in saying that I will not enter into dis-
cussion with such opponents. The literature of the last decade
furnishes so many cases where persons who, after their own more
or less special occupation with diatoms, look upon themselves as
important microscopists, bring to light the greatest imaginable
nonsense relating to sculpture questions. If I cannot indulge in
the hope of putting a stop to this by my present work, it will
no doubt contribute much for the intimate knowledge of these
interesting organisms, and when in future the structure of these
cell-walls is in question, the works of Pfitzer and Miller will
not be exclusively referred to, but precedence will be given to
an investigator who ten years ago put the leading facts into
clear light.
Lastly, I have to thank those scientists who sent me their
papers, also Herr Moller, of Wedel, for sending various material for
investigation.
EXPLANATION OF PLATES.
All the figures have been drawn by the excellent 1/18-in. objective of Dr. Hugo
Schroder. All are magnified 1550, unless otherwise stated. The variety in the
amplification is due to the change of the eye-pieces and the alteration of the
correction-adjustment. They are, with the exception of fig. 7, no flighty
sketches, drawn after mere eye measurements, but all dimensions are based
on micrometrical measurements.
The Structure of Diatoms. By Dr. J. H. L. Flogel. 687
Puate VIII.
Figs. 1-7.—Pinnularia major.
ha, showlet
me, median
1 e, lateral \ ends of the same.
k 6, entrance to the chamber.
mn aes } edge of the opening.
m i, mid-rib.
Fig. 1—Transyerse section through a valve touching the chamber-openings
somewhere in the line at 4 in photograph 1 (or perhaps nearer the central
nodule).
Fig. 2.—Transyverse section about the same place, line 5, in which is contained
the vertical. partition-wall between two chambers, the openings indistinct.
Fig. 3.—Middle portion of a sim'lar transverse section to illustrate a very
common appearance of the sloping away of the middle furrow. s, the closing
envelope which in many cases is torn during cutting, whereby balsam enters
into the cleft and produces the appearance of a continuous cleft through the
entire membrane.
Fig. 4—Transverse section touching the centre of the central nodule (line 3
in photograph 1).
Fig. 5.—Part of a longitudinal section touching the chamber openings, i. e.
in the direction of the dotted line 1 in figs. 1 and 2, or photograph 1. af
outer surface, and if inner surface of the cell-wall; % wv, a vertical partition-
wall between two chambers. .
Fig. 6.—Portion of a longitudinal section along the side of the cliamber
openings, i.e. in the direction of the dotted line 2 in figs. 1 and 2, or photo-
graph 1. ‘he membrane on the inner surface is much stronger than that on the
outer surface.
Fig. 7—Diagrammatical figure of a collodion cast. a, a single T-shaped
continuation in side view (as it becomes elucidated by the different focal
positions). }, a group of the same, in perspective as seen from above. 2, the
smooth collodion surface. c, a piece of the serrated stripe which is formed
along the chamber openings, and on which the 'T continuations stand like a row
of trees. x, the collodion thread which was in the chamber. y, the spine of the
same, which in consequence of the collodion contained in the opening contracts.
Fig. 8.—Pinnularia (Naviculi) Crabro.
Transverse section from the middle of the valve. % a, chamber; & 6, opening
of the same. yg}, girdle-bunds; the outer has in all sections the pusition
figured; the second valve is wanting.
Figs. 9-12.—Navicula Lyra.
Three sections out of a series of 27 transverse sections through one valve.
Fig. 9—Middle section (No. 13) touching the central nodule mk, which
forms at that point a very flat thickening. 4a, chambers.
Fig. 10.—Four sections further on (No, 17). mr, mid-rib. / p, lyra plates.
k a, chambers.
Fig. 11—Section near the end of a valve (No. 1).
Fig. 12.—Small portion of the surface-view of a valve of somewhat consiler-
able size, corresponding to fig. 10.
Puate IX.
Figs. 13-20.—Surirella biseriata.
q |, transverse ribs.
m 7, mid-rib.
fl, wing.
rr, marginal tube in the wing.
688 Transactions of the Society.
Figs. 138-19 x 830.
Fig. 13.—Transverse section No. 2
” 4. ” ” » 9
Pela: re 9 », 39 ) through one and the same valve.
” 16. ” ” ” 40
9 17. eae ”? 9 66
» 18.—Portion of the longitudinal section No. ) through one and the same
», 19.—Longitudinal section » 8) valve.
20.—Portion of the section No. 8.
The longitudinal section, fig. 19, corresponds to the dotted line in the
transverse sections figs. 15 and 16. In figs. 13, 15, and 16 the more faint contours
indicate the outlines of the membrane with slight change of focus, corresponding
to the undulations in fig. 19. The small continuation f at the edge of several
transverse sections is probably due to the adhesion of the girdle-band.
The thick longitudinal section fig. 18 comprises nearly the entire wing; the
fig. in consequence shows a portion of the wing in surface view. a, the places
where both membranes of the fold cling together, corresponding to fig. 14 in
transverse section. 6, the folds, but not clinging together, i.e. the tubes which
connect the cell-lumen with the continuous marginal tube, corresponding to
fig. 15 transverse section.
Figs. 21-22.—Triceratium Favus.
Fig. 21.—One end of a section going nearly through the middle of a valve.
a f, outer surface. if, inner surface. 7/, marginal ridge. x, portion where the
section goes through the hexagonal prismatic chambers, consequently touching
the chamber-openings £6. , portion of a section near the edge of a chamber,
consequently the vertex shows a connection of the heads of the net-lines,
d, spines in the angles between the hexagons. g 7, basal membrane.
Fig. 22.Similar section, touching the middle of one of the three pro-
tuberances.
Figs, 28-8.—Coscinodiscus radiatus.
Fig. 23.—Marginal portion of the middle section of a specimen at the moment
of division (from the Norwegian coast). g7’, basal membrane of the original cell.
g vr’, basal membrane of the valve in process of formation. g 0}, the girdle-bands.
a s, the nodule of which mention is made in the text. pr, protoplasm.
Fig. 24.—Marginal portion of a middle section through an undivided specimen.
The letters have the same signification as in fig. 23.
Fig. 25.—The first section from the series from which the preceding was
taken; the girdle-band g 6 in surface view with the very small chambers of the
margin r k.
Fig. 26.—Small portion of the surface view of a specimen (from the mar] slate
of Oran) focused to the plane indicated by line 1, fig.23. & 6, chamber openings.
Fig. 27.—Similar portion with slightly lower focal adjustment, line 2, fic. 23.
ne 28.—Portion of a specimen from the edge with abnormally thick chamber-
walls.
Fig. 29.—Coscinodiscus oculus iridis.
Small portion of a vertical section. a f, outer surface, ¢ f, inner surface of the
membrane.
Fig. 30.—Coscinodiscus centralis.
Portion of a section through a valve with unusually coarse marking. a f,
outer surface; 4 f, inner surface.
Fig. 31.—Coscinodiscus concinnus.
Portion of a thin section; outer as well as inner surface can only be distin-
guished at the common curve (not figured).
Fig. 32.—Zupediscus argus. (Omitted.)
The Structure of Diatoms. By Dr. J. H. L. Flogel. 689
PLaTEs X. AND XI.
Figs. 33-52.— Achnanthes brevipes.
mk, central node.
ds, dorsal valve.
vs, ventral valve.
r 7, marginal ridge (r /’ old, r 7” young).
g 6, girdle-band.
s z, marginal view of the same.
Fig. 33 x 670.—A chain consisting of two young frustules. The cell on the
left is figured in full detail in the manner usually adopted in representing diatoms ;
i.e. by focusing as a whole. The cell on the right is naturally similarly con-
ditioned. The transverse lines are only indicated, but for the central part the
highest focus has been chosen for the representation ; it brings to view the
marginal strie s z’ of the old girdle-band. Further on towards the edge it is
focused a little lower ; then only are seen the very short dotted striz s z’’ of the
young girdle-band between the two marginal ridges. In the cell on the right,
near one end, the young ridge has separated considerably more from the old
one than at the other end. The numbers refer to the direction of the sections,
figs. 40-2.
Fig. 34.—The upper edge of the preceding fig. under exact medium focus.
The marginal ridge shows a saddle-shaped depression, the small elevation is the
young ridge in process of splitting away from the old one. The depression
between the two must be looked upon as the first visible indication of the young
girdle-band. The old girdle-bands extend one over the other only in the
direction s. The cells are without doubt completely closed. The girdle-band is
raised at the marginal ridge slightly. Marking of the surface view given with
the valves below.
Fig. 35 x 670.—A chain similar to the preceding, but a little older; the
young marginal ridges r /” are further apart from the older r 7’. Only the stria
of the young girdle-band s z” are represented.
Fig. 36.—The upper edge of the left cell in fig. 35, in order to bring to view
the relation between the two marginal ridges and the doubly thick membrane
between them.
Fig. 37 x 670.—An older cell, probably shortly before division. The peculiarly
interrupted striated marking of the girdle bands is given. This is about the
most complicated striation of all; between this and fig. 35 one finds all transitions.
It seems as though the boxed-up girdle-band had already separated from its
marginal ridge.
Fig. 38 x 670.—A dorsal valve and
Fig. 39 x 670.—A ventral valve viewed from the surface with full marking.
Fig. 40 x 660.—Transverse section No. 1,
ae % » 90, and
pee 7 = aD
out of a series of 23. They correspond to the dotted lines 1, 2, 3 in fig. 33
(naturally with the modification that we have here to do with a chain of three
frustules). Fig. 40, extreme marginal section which has touched only one
portion of the lowest cell. Fig. 41, the middle cell partially injured in cutting.
Fig. 42, the uppermost cell crumbled out.
Fig. 43.—Transverse section No. 12 of the same series. The uppermost cell
uite uninjured. Quite distinctly is here observable the difference in size between
the old (r/’) and the young (r/") marginal ridge; the hook shape of the former
also visible. The valve membrane is distinctly dotted (as expression of the dots
between the transverse lines in the surface image). mr, mid-ribs,
Fig. 44.—Portion of the same uppermost ceJl from the transverse section
No. 9 of this series. The adjoining cell is split off whereby the duplex of the
irdle-band becomes distinct, because in consequence of the fracture both mem-
ranes have separated; gb’ the old, gb" the younger girdle-band.
Fig. 45.—Portion of the ventral valve of this uppermost cell to show the mid-
rib mr and the surrounding fine spaces as in the sections Nos. 8 and 16 of the
above series. ‘The fine line q is the inner limit of one of the transverse stria.
690 Transactions of the Sociedy.
Fig. 46.—The dorsal valve of a cell with the cell-nucleus from the second
transverse section series.
Fig. 47 x 660.—Longitudinal section through a ventral valve in the direction
of line 4, fig. 33.
Fig. 48 x 660.—Longitudinal section through a dorsal valve in the direction
of line 5, fig. 33.
Fig. 49 x 660.—Section quite through the girdle-band in the direction of
line 6, fiz. 33. :
Fig. 50.—A portion of fig. 47,
”» Le ” ” ’
”? 52.— ” ” 49,
highly magnified. q, the ridge-sl.aped transverse lines projecting inwards. p, tl.e
fine dots between them (? chambers).
Fig. 53.—Synedra Gullionii.
Any middle transverse section through a frustule.
EXPLANATION OF THE PHOTOGRAPHS DEPOSITED IN THE
LIBRARY.
All photographs cxcept No. 12 have been made by me personally without
eye-piece accurding to the old method with wet plates. No touching up has
been done to any of them. No faults in the negatives are specially mentioned,
but they can easily be distinguished from the objects used in demonstration.
1. Pinnularia major; large specimen in balsam; a little more than half a
valve. Produced by Schroder’s immersion 1/18 in.; x 631.
The lines on the tracing paper covering the pl:otographs which can be con-
nected by a ruler, indicate the direction of the sections in the space between
a and 6 :—
1 is the direction of the longitudinal section fig 5, photograph 3.
2 a - 6, and portion of photograph 2.
3 as transverse section 4.
4 ” ” 1.
5 ” ” 2.
6 = oblique section, photograph 7.
7 x transverse section of the valve m in plotograph 6.
On the right-hand side the chamber openings are distinctly seen; in making
line mr the median edges of these edges are t.uched; in the same manner Jr
will touch the lateral edges. On the left and in other places on the valve the
focus is nut so good, although both edges glimmer everywhere.
From c to d is the region where presumubly the mid-rib shows the depression
almost at right angles on the transverse section (fig. 3). From c¢ to the end-
nodule ¢, and from d to the line 7, the mid-rib is simply a vertical incision (fig. 1).
f, irregularly formed chambers on the right; the walls are here black and vanish
at the lateral end.
2. Pinnularia major. A coarser longitudinal section through two valves lying
one in the other. Like all other following sections, so here the section is im-
bedded in gum, the entire gum-chip surrounded by balsam. Position and
mignification asin 1. The focus from a to } is the best; one sees in the valve
on the right the transverse sections of the chambers with the inner membiane
which closes the chambers; the section direction is approximately the sume as
with line 2, photograph 1. In the valve on the left the opeuings are seen, but in
consequence of the great thickness of the section the oblique ridge-shaped
vertical chamber-walls glimmer and disturb the image, and which only becomes
quite intelligible by photographs 3 and 7. In the lower part is a zigzag-shaped
cleft r through the gum-chip; there the section is very thick and the focus
unsuitable. This will convince us what errors can arise with a coarse object
through mistakes in focus and cutting, and which in a less degree occur with finer
objects like /’leurosigma. he valve on the right Las lost the outer membrane,
which has apparently stuck on the gum on the right; the vertical chamber-walls
are therefore toin off at the pont of connection with this outer wall, aud the
The Structure of Diatoms. By Dr. J. H. L. Flégel. 691
chambers erroneously suggest an outer opening. In the left valve these vertical
chamber-walls appear on the inner side serrated (naturally, with both, the inner
surface is on the left); this also is an optical delusion. In both valves the very
dark walls are much thicker and more clearly expressed than in a reliable image;
but the lumen of the chambers is reduced and strongly rounded off (also wrong !).
The connection between the vertical walls with outer and inner membrane
appears therefore like a thick nodule; whilst with good sections little can be
traced of such end thickenings.
3. Pinnularia major, Extremely thin longitudinal section exactly through
the chamber-openings, focus and magnification as in 1. This is probably the
best section in my collection, and can be recommended for all finer measure-
ments. The best focus is from a to b; less good from 6 to c. The section
direction runs in the line 1, photograph 1. One sees (best with the help of a
lens) the club-like thickening of the chamber-walls; one can measure the
thickness of the outer membrane, &c. The inner surface is on the right, proved
by the bend in the section. On the left is a surface section of another valve.
4. Pinnularia major. Collodion impression of the outer surface of a valve,
in air. Produced by Schréder’s dry 1/6, x 298. The strongly black mar-
ginal line is the expression of an elevation in the collodion originating in
the same manner as we shall see when we come to photograph 5. The mid-
rib is distinctly seen; it is a delicate ridge, corresponding to the cleft in the
valve, and ends at the central nodule with a stronger point. The smooth space
on both sides of the mid-rib slopes, beginning at that portion of the surface
where the chambers are situated in the valve, and is there slightly different ;
this difference probably originates by a change in the evaporation processes.
Starting from the upper corner on the right we observe on the cast a chain of
numerous small crystals of unknown origin (on the preparation itself). The lines
on the left are Newton’s rings in the thin collodion film. All other dotting
is the granulation of the collodion surface.
5. Pinnularia major. Collodion impression of the inner surface of a valve.
Produced as No. 4, same magnification. With regard to the general sketch of
the valve the following is to be observed:—If in making a collodion cast of a
valve (shown in fig. 119 as s) lying with its surface towards the slide (4), the fluid
naturally fills up at first all the inner spaces. In hardening the mass contracts,
and occupies afterwards as a solid film the shaded space c in the image. The
quantity that originally entered into the angle between valve and glass thins
away and appears as projection »; this accounts for the remarkable enlargement
of the outline in the cast in comparison with that of the valve. Next to the so-
formed dark surrounding edge follows an inner portion partly lighter, partly
darker, and often interrupted. This is the depressed furrow in which lay the
extreme edge of the valve (vide photograph 6), and had been so squeezed into
the collodion that during the separation trom the valve many small fragments
of this sculptureless edge remained behind in the furrow. On the surface
one observes the impression of the central nodule, and further two longitudinal
lines. These represent the collodion which ran into the chambers (vide text),
and are raised ribs (#6 in the fig.). In several places are seen the threads
described in the text. A part of this longitudinal line is drawn in fig. 7;
conf. their description. (These raised ribs I have sometimes seen on casts
of extremely small undefined Pinnularia ; one would otherwise only look for them
in Navicula. The real details can only be learnt from large varieties.) On
the left of the cast a large air-bubble had been enclosed in the collodion;
near its centre we observe the granulation, elsewhere so distinct, decrease, which
circumstance I have made use of for the explanation of the faint granulation
692 Transactions of the Society.
above the chambers on photograph 4. In the centre of the bubble Newton’s
rings. The Stauroneis valve lying at the side is not free from the collodion.
6. Pinnularia major. A number of exact transverse sections. Produced like
No. 1, x 647. The section made after method I. is of exquisite thinness
and flatness. It was photographed a few days after being made, therefore the
little air-bubbles which ought to be formed in the chambers during the hardening
of the gum are visible, whilst with other sections kept for some time they have
been mostly absorbed by the balsam. Altogether transverse sections of twenty
valves can be seen, and they are lettered A to U. Of A and B only portions are
seen, but the others are entire.
The focus on the left not very good; on the right chamber opening very fine;
at the lateral edge of the same an oval air-bubble in the chamber.
D, focus in the left not suitable; on the right median end of the chamber,
and median edge of its opening fairly good; in the extreme lateral end of the
chamber an air-bubble.
E, similar section to M, but broken in the middle line; on the left median
end of the chamber pretty good.
F, broken up and useless.
G, a tolerably good transverse section, a little broken up; chambers indistinct;
mid-rib good; has the angle-depression of fig. 3.
H, only good above; shows the fine pointing of the valve margin very sharp ;
in it several air-bubbles ; lower down, broken up.
I, quite similar.
K, very beautiful section; chamber opening on the left is good, but not
so distinct on the right; mid-rib is observable as a delicate cleft not quite
through.
L, similar section, mid-rib burst; on the left, chamber and its opening very
fine; a few air-bubbles in the lateral end do not interfere much.
M, one of the most magnificent sections, quite close to the central nodule
(corresponding to the line 7 in photograph 1). The mid-rib is here an unusually
deep vertical narrow cleft ; one sees the closing envelope very distinctly (with a
lens); chamber of the upper half good, that of the lower indistinct, because only
the partition-walls remain (like fig. 2).
N, only the lower good, crushed at the top.
O, central nodule section, hardly of use.
P, useless.
Q, apparently central nodule section, but injured ; focus unsuitable.
R, focus unsuitable; the chambers can be recognized in outline.
8, particularly beautiful, showing the mid-rib as a right-avgled bent cleft, like
fig. 2; the chambers are tolerably good in the upper half.
T, chamber of the upper half very good, also its narrowed lateral end; the
mid-rib is broken, and the lower half useless.
U, good section, but the focus not sharp ; both chambers visible.
The section encloses a girdle-band section.
7. Pinnularia major. Slightly oblique longitudinal section, produced like
No. 1, x 650. This is another most elegant section in the direction of line 6 in
photograph 1, and represents the end portion from line 4 to f. This, like
photograph 3, is very suitable for all finer measurements under the lens. The
following are chiefly remarkable :—In the region a the vertical division-walls
thickened below between the chambers; the openings of the chambers; the very
thin outer membrane. At the point 6 the lateral edge of a chamber opening is
touched, and there appears in great strength the inner membrane (closing the
ehamber below). At c, is a favourable image of a chamber lumen: the thin
outer membrane, the more than twice as thick inner membrane, rounding off of
the square transverse section of the lumen at the inner membrane.
8. Hupodiscus argus. Middle section through a valve. Produced with
Schréder’s 1/6 dry objective, x 298. On the left is observed the inner cavity
in which is an air-bubble at the end. In the middle region is a faint indication
of vertical chamber-walls. Spine-like points are observable on the lower outer
surface of the valve, similar tu Ziiceratium spines.
9 and 10. Pleurosigma balticum. Transverse sections, produced like 1, x 669.
The section is made after method I. (in pure gum in collodion), and was photo-
The Structure of Diatoms. By Dr. J. H. L. Flogel. 693
graphed a few weeks after. It is No. 76 out of 150 transverse sections. Through
a number of 14-16 frustules, partly parallel, partly one on the other. Image 9
was taken with somewhat higher focus, and image 10 with lower focus; the
ditierence is naturally very insignificant. For the examination of these two
images and of photograph 11 a lens should be used. For the representation of
the sculpture my former description of the transverse sections of P. balticum
should be referred to (6, pp. 481-5, figs. 13, 14 and 15). The separate frustules
are marked A-L. For the comprehension of the arrangement of the frustules in
comparison with photograph 11, we must observe that only the Pleurosigm A to
D are in the original position, that the gum section on the right of D on account
of extreme thinness is broken off, and that this broken-off and still further broken-
up portion has fallen obliquely across the other portion which remained intact.
The thinness of the gum-chip in this instance can be best estimated by noting
that hardly any trace of the collodion limit lines can be seen (vide photograph 11),
which must have existed below BK and D, About the separate sections the
following is to be observed :—
A, very thick section, kidney-shaped within. The left valve is broken in the
middle, only the one half is seen. The right valve is broken up, but both the
chief and secondary ribs, with a portion of thin membrane attached to the former
distinctly visible; the chambers slightly indicated.
B, a slightly tlinner section, strongly notched witlin. The left valve twice
fractured; the right valve quite uninjured; only well focused in image 10; the
tain membrane-stria next to the mi'-rib very beautiful; slight indication of
chambers ; the girdle-band at the top is in normal position, below out of place, in
photograph 10 clearly duplex.
C, section thinner than B. Content wanting. The upper valve uninjured.
Best focus in photograph 9; indication of chambers very good, particularly in the
left half; a depressed furrow beside the mid-rib god, also the secondary rib,
The lower valve is broken in the thin portion, although both halves are not much
displaced. Focus in both images not exact. The left girdle-band is injured ; on
the right clearly duplex; bvuth still adhere to their original valve, although
slightly displaced one towards the other.
D, this magnificent central nodule section, which forms the chief object of
representation, and is rendered on a larger sale in photograph 12, I shall describe
further on.
E, injured section, only the lower valve good. The content adheres to the
girdle-band. On the left a few fragments of valve transverse sections.
F, a much injured section. The upper valve broken in two pieces, but the
fracture is not in the thin membrane stria; the half lying a little higher shows
in photograph 10 very good indications of chambers; the lower half to which is
attached the content is not so good; tolerable in photograph 9. The lower valve
broken up; the girdle-band has got out of place.
G, imperfect section, which very clcarly proves what kinds of deception can
take place in researches not conducted critically. In the half-valve on the right
at the top one sees in photograph 9, without much trouble, the outlines of a base
membrane, with ridge elevations noded at the ends. A little more imagination
will add outer openings of the chambers. Photograph 10 destroys all these
illusions, and proves at the same time that this section is much too thick for such
studies; it is almost exactly the reduced copy of Pinnularia, photograph 2 at r
(vide supra).
11. Pieurosigma balticum, Everything like 9 and 10, except the transverse
section No. 80 out of the same series (Nos. 77-8-9 were useless fragments
cut through totally different portions of the bundle). This image chiefly
serves to show that by using my section method the separate frustules can be
identified from section to section, whereby real series of sections can be obtained.
A to D can be easily recognized by comparing with images 9 and 10. Below
B D E run two slightly bent parallel lines through the field of view; these form
the limit of the transversely cut delicate collodion film on which the arrangement
of the Pleurosigma took place. On the right of E the section is broken off and
another gum-chip has fallen obliquely on it; the frustule sections H and I
therefore lie one upon the other. For the separate scctions the following remarks
may be serviceable :—
694 Transactions of the Society.
A, very thick and useless, in some places indications of chambers.
B, scarcely better; the right valve has possibly a useful thinness, but is not
distinct.
C, has in the upper valve the deceptive image described above with G.
D, the focus is tolerably good only for the lower valve, where at the same
time is visible how the image of the central nodule transverse section passes over
into the ordinary transverse section image.
E, F, G, focus entirely wrong.
H, shows specially the asymmetry of the secondary rib, exactly as I have
described above (fig. 13). Indication of chambers in some places good.
I, indistinct.
K and L, two fragments of valve sections, the former showing the chambers
very well.
42. Pleurosigma balticum. The frustule D from the photograph10. Enlarged
from the negative by means of the ordinary portrait objective. Total magnifica-
tion, 2340. The image has been made, fearing that the delicacies of the negative
during the printing would suffer considerably, and further to facilitate measure-
ments. “The valve a’ is uninjured throughout, and gives an unblemished picture
of the central nodule. The chambers disappear to the eye at some distance
from the centre. Instead of the usual membrane-thinning commencing with
mid-rib and secondary rib, the wall remains solid throughout (6’), but has two
very small projections inwards (c’), between which is a slight depression. The
chamber-walls are here distinct, the cavities dark ; the focus of photograph 9 is
for this valve more advantageous. The valve a” is uninjured in the lower half,
but the two projections c” of the central nodule are still visible; evidently here
has been the extreme fine edge of the section. By comparing photograph 9 with
it one detects faint traces of this lower half-valve, which we find again indicated
in photograph 12. From the preceding we deduce that this section of the upper
half-valve is sufficiently thin for the minutest investigations. The chambers are
seen in full clearness and in such accordance with my former diagrams as if this
preparation had served for them as model. The girdle-band g }’ is not quite
distinct, in consequence of being crumbled; the other g 6” partly covered by the
section of the frustule E.
I have formerly given the greatest thickness of the cell-wall as 1°8. Con-
sidering what is clear in the valve a’ and what is dark in a”, and that one must
not reckon in a' the dark seam beyond the clear space, we get in this photograph
the greatest thickness of the wall near the central nodule as 4-2 mm., consequently
2
the true thickness is =- =1'8y. The height of a chamber lumen may be
estimated at 1/3 of this size; therefore these are all valves not beyond the power
of microscopical observation.
Valve E a belongs to frustule E, also the girdle-band E g 6 and the contained
portion E 7. In the former is seen the indication of chambers tolerably well; the
same may be seen in the valve fragment lying on the left.
13 and 14. Triceratium Favus. Section No. 11 from a series of 19 vertical
sections through a valve. Fig. 13 with high focusing; fig. 14 with low focusing.
Produced with Seibert and Krafft's immersion VII. 6; x 652. The inner surface
of the valve is turned downwards.
15 and 16. Coscinodiscus radiatus. Middle section from a series of 31 vertical
sections through a specimen in process of division. Produced like No. 1;
x 660. Fig. 15, for the greater part of the section correct focus, especially reliable
in the centre and a little lower. Here are the T-figures of the chamber-walls
distinct, also the four base-membranes. Of less use is the lower end, although
pretty distinct. For the upper end the focus is unsuitable. Image 16, gives the
correct focus for the upper end, but not so well for the lower end; the middle is
quite unreliable. At both ends is secn the overlapping of the thick girdle-
ands.
17. Triceratium Favus, Thin but not quite plane section. Produced like 1;
x 680. The section direction is not exactly through the middle of the hexagons,
therefore every pair of chamber-walls are brought closer and connected on the
outer surface (on the left), and thus between each pair there is a slightly larger
The Structure of Diatoms. By Dr. J. H. L. Flogel. 695
space (a); here the outer entrance-opening is touched (6). The section is only
thin enough and focused correctly at a. Below, near the marginal portion,
another piece of diatom lying by accident on the valve has been touched.
18. Surirella biseriata, Collodion cast in air. Production and magnification
like photograph 4; it is the cast of the inner surface of a valve. The deep
black edge is a raised collodion ridge, which is formed on the outer side of the
wing as described above with Pinnularia. The distinct border next to it is a deep
brown of the collodion; in it must have been the valve edge (figs. 13-17). The
dark ribs on the surface are raised places, i. e. wave-elevations, the clearer inner
spaces are depressions. At the lateral end of each wave-elevation, not far from
the distinct marginal line, is a dark dot. In the cast is a vertical projection;
these thorn-like spines naturally are the contracted outlets of the channels. In
the mid-:ib a stria of the valve has remained behind. Collodion surface remark-
ably smooth.
19 and 20. /sthmia enervis. Two successive sections, Production asin1; x 633.
The one section must be adjusted to the other like a mirror image. The separate
sections are A, B,C. The situation of the cells in the gum has unfortunately not
been figured before cutting, and it is now almost impossible to define them; but
so much is certain, a few sections further on A and B coalesce, consequently both
belong to one cell, whilst C is a second cell, apparently touched nearly trans-
versely. B is therefore, as its small extent teaches, doubtless a section through
the extended end of the rhomboidal cell, either through a free corner or more
probably through the isthmus proper. This is here important. 19 is a very thick,
20 is a very thin, section in which the isthmus section is a little injured; the
section of the cell C is flapped over at the top or pushed together. In both
sections one sees in the ring B on the inner side ridge-projections, which are the
cause of the well-defined cell-marking. Had I given this with only one section,
some severe critic might have retorted that the ridges might be on the outer side,
and that the apparent inner projections were obliquely struck in projecting
marginal portions. Such like opposition is refuted by the image of the second
section. Designating here the projections, for example, 1, 2, 3, &c., one will find
that all fit exactly one to another except that, instead of No. 3, photograph 20,
we see two projections standing close together in photograph 19, evidently because
here in the first instance an areola corner was touched. This comparison proves
further, that the membrane was touched exactly vertically by the section on the
right side in photograph 19 (or on the left in photograph 20), but on the opposite
side obliquely. The more reliable thinner section 20 proves undoubtedly the
turning-in of the ridges and the outer smoothness of the membrane.
The section through the cell C is by far too thick for the study of the
sculpture. In section A are found a few places in photograph 19 (just below the
middle), where it has the required thinness for the observation of the very thin
ridges on the outer side of the membrane. Judg ng from the numerous examples
of these images in other sections I cun only declare it to be the girdle-band.
BIBLIOGRAPHY.
1. Aspe, Prof. E—Beitrage zur Theorie des Mikroskops und der mikrosko-
pischen Wahrnehmung. Arch, f. Mikr. Anatomie, ix. pp. 413-68.
2. Dexy, F.—Note sur Vargile des Polders suivie d’une liste de fossiles qui y ont
été observés dans la Flandre occidentale. Annales de la Société Malaco-
logique de Belgique, xi. 1876.
3. Dirre, Prof, L.—Beitrage zur Kenntniss der in den Soolwassern von Kreuz-
nach lebenden Diatomeen, sowie iiber Structur, Theilung, Wachsthum
und Bewegung der Diatomeen iiberhaupt. Kreuznach, 1870.
4, EnGeLmAnn, Prof. Ta. W.—Neue Methode zur Untersuchung der Sauer-
stoffausscheidung pflanzlicher und thierischer Organismen. Botanische
Zeitung, 1881, pp. 441 et seq.
5, Fioce.—Ueber optische Erscheinungen an Diatomeen. Bot. Zeitung, 1869,
pp. 713, 729, 753.
696 Transactions of the Society.
6.
7.
8.
F.Lé6cEeL.— Untersuchungen iiber die Structur der Zellwand in der Gattung
Pleurosigma. Arch. f. Mikr. Anatomie, vi. pp. 472-514.
— Ueber die Structur der Diatomeenschale. Tageblatt der Versamm-
lung deutscher Naturforscher und Aerzte zu Leipzig, 1872, p. 141.
— Ueber die quergestreiften Muskeln der Milben. Arch, f. Mikr.
Anatomie, vill. pp. 69-80.
Die Diatomaceen in den Grundproben der Expedition zur Unter-
suchung der Ostsee. Bericht der Pommerania-Expedition, pp. 85-95,
1883.
. Hatiier.—Die Auxosporenbildung bei Cymbella gastroides Kiitz. Zeit-
schrift, Humboldt, April, 1882.
. Just, Prof.—Botanischer Jahresbericht 1873, &c.
. LevcKart, Prof.—Die menschlichen Parasiten und die von ihnen herriilr-
renden Krankheiten. Ite Aufl. 1863.
. Morenouse, G. W.—Silica Films and the Structure of Diatoms. Monthly
Microsc. Journal, xv. p. 39.
. Miter, Orro.—Untersuchungen iiber den Bau der Zellwand von Triceratium
Favus Ehr. SB. der Gesellschaft naturforsch. Freunde zu Berlin vom
17 October 1871, pp. 74-81.
. —— Ueber den feineren Bau der Zellwand der Bacillariaceen, insbesondere
des Triceratium Fayus Ehr., und der Pleurosigmen. Reichert’s und Du
Bois-Reymond’s Archiv, 1871, pp. 619-43.
. —— Ueber den Bau der Zellwand der Bacillarien-Gattung Epithemia Kitz.
SB. der Gesellschatt naturforsch. Freunde zu Berlin vom 15 October 1872,
pp. 69-71.
. NAGELI und ScHWENDENER, Profs.—Das Mikroskop. Theorie und Anwendung
desselben. 2nd ed. 1877.
. Privzer.—Ueber den Bau und die Zelltheilung der Diatomeen. Bot.
Zeitung, 1869, p. 774.
. —— Untersuchungen iiber Bau und Entwicklung der Bacillariaceen
(Diatomaceen). Botanische Abhandlungen von J. Hanstein, i., 2, pp. 1-
189. 1871.
. — Die Bacillariaceen (Diatomaceen). In Encyclopaidie der Naturwissen-
schaften, Handbuch der Botanik von Prof. S:henk, 1882, ii. pp. 403-45.
. Prinz, W.—Etudes sur des coupes de Diatomées observées dans les lames
minces de la roche de Nykjobing (Jutland). Ann. de la Société Belge de
Microscopie, vii. 18 0.
. Rasennorst, Dr.—Flora europea Algarum aque dulcis et submarine.
Sectio I. 1864.
. ScHumann, J.—Die Diatomeen der hohen Tatra. 1867.
. Scouttze, Prof. M.—Die Bewegung der Diatomeen. Arch. f. Mikr.
Anatomie, i. pp. 376 e¢ seg. 1860.
. Stack, H. J.—On the structure of the valves of Hupodiscus Argus and
Isthmia enervis, showing that their siliceous deposit conforms to the general
plan of deposition in simpler form. Monthly Microsc. Journal, viii.
(1872) p. 256 ; i. pp. 123, 186.
. SrurHENson, J. W.—Observations on the optical appearances presented by
the inner and outer layer of Coscinodiscus, when examined in bisulphide of
carbon and in air. With 1 plate. Monthly Microsc. Journal, x. p. 1.
. SvRasBuRGER, Prof. E.—Ueber den Bau und das Wachsthum der Zellhaute.
Jena, 1882.
. Weiss, Prof.—Zum Baue und der Natur der Diatomaceen. SB. der k, Acad.
der Wissenschaft, I. Abth. 1871, Feb., pp. 1-37.
. Weis, S.—The structure of Zupodiscus Argus. With 1 plate. Monthly
Microse. Journal, ix. p. 110.
C 69% <)
XVIL—On Drawing Prisms.
By J. AntHony, M.D. Cantas., F.R.C.P., F.R.MS.
(Read 11th June, 1884.)
Wen the scientist is investigating matters of special interest by
means of the Microscope, he naturally wishes to record pictorially
what he sees, and particularly if the objects under examination
should chance to be of a perishable nature. If he has not under-
gone some sort of artistic training, his efforts with the pencil will
generally fail lamentably to convey an idea of what he sees in the
Microscope; his drawing will probably be utterly wanting in
“character,” and his outlines poor and uncertain—shortcomings
which he will probably try to make up for by a painful elaboration
of detail. This is not altogether a fancy picture. A man may
have a most intense and learned appreciation of what the Micro-
scope reveals to him, and yet be utterly unable to make a reliable
sketch, much less a picture. It is under such circumstances that
inventive brains have been stimulated to devise appliances which,
placed upon the eye-piece of a Microscope, should, by well-known
laws, project the Microscopic image on to a blank sheet of paper in
front of the observer, who would be enabled to trace with the point
of a pencil the outlines and salient points of the shadowy micro-
scopic image.
This is, of course, a very rude description of the general action
of all the mechanical aids to drawing from the Microscope, but
further on we shall see that special means have been devised to
attain special ends.
Three questions have repeatedly been put to me.
1. What is the special advantage of using a drawing prism ?
2. Does it require a knowledge of drawing to use it ?
3. What form of prism will be the best to employ ?
The answerto the first question is easy. The employment of
a prism means an enormous saving of time, and not only that, but
used with simple precautions, it means the power of delineating
with almost rigid accuracy the outline of all objects seen in the
Microscope. And this is not all the advantage, for an absolutely
identical magnification can be insured in every successive drawing
by simply marking on the Microscope a fixed observing or sketching
angle, and by using for successive sketches the same objective and
same ocular duly armed with the prism. As each drawing is com-
leted, a simple substitution of a micrometer on the stage of the
nasa allows a “scale” to be projected on to the drawing, or
on the side of it, which may be thus said to have received its
official stamp.
Ser. 2.—Vo, IV. 3A
698 Transactions of the Socvety.
To reply to the second question :—Most assuredly no special
knowledge of drawing is needed for making accurate outlines
with the aid of a prism; little more than the first lesson in free-
hand drawing is required, viz. the power of tracing lines with
firmness and certainty of touch.
The third question, as to the best form of prism, will be met
by a short review of the various forms of drawing appliances from
the days of Wollaston, who devised a prism which in many of its
qualities has never been surpassed. In making such a review this
evening, as I shall have to “name names,” it need hardly be said
T shall strive to keep within the bounds of fair criticism, and
especially to eschew invidious comparisons. Time would not allow
me to go into the optical construction of the various appliances
which I shall have to bring before your notice ; all these particulars
can be learned from the back numbers of our Journal. I prefer to
take these little adjuncts to the Microscope just as they were sup-
plied to me by their more or less sanguine inventors, and to narrate
what they have respectively done in my hands, premising a hope
that as I have had one or the other in pretty constant use for some
forty years, a description of their performances will neither be
unwelcome nor unprofitable to the practical microscopist.
In illustration of the remarks I have to make, and as showing
the various applications and “all round ” character of the drawing
prism—and particularly in its more recent forms, I venture to
exhibit selections from among the thousands of drawings I have
made, choosing those which may be said to be typical of the uses
of the prism.
The subjects are, as you will see, of all sorts, but having this in
common, that they were all drawn under the Microscope; all out-
lined by the prism. When you see copies from photographs, from
book-illustrations, magnifications of the exquisite engravings in
Yarrell’s ‘British Birds,’ and Bell’s ‘Reptiles’—such as the
venomous and non-venomous snake—and proceed from these low-
power magnifications through the whole range up to the delinea-
tions of living diatoms as seen with my grand Tolles 1/25 objective,
I think you will feel an incipient respect for the use of the little
instrument, the use of which I advocate. Just let me call
attention to the important fact, that in each rapidly executed copy
of an engraving, every mark of the graver’s tool has been indicated
at one operation by pen and ink while still under the Microscope ;
and in mere outlines of microscopic objects—whether executed with
pen or pencil, all have been purposely left as they were traced under
the instrument ; or to use other words familiar to drawing academies,
they have not been “tcuched up.”
Ag an example of the satisfactory character of this untouched
outline, I hand round copies of the well-known Plewrosigma
On Drawing Prisms. By Dr. Anthony. 699
angulatum, as executed with various prisms, the sketch of each
having occupied as nearly as possible half a minute! Those who
have sketched P. angulatum will be conscious that several minutes
are generally needed to get the peculiar curves of this diatom
satisfactorily. Here are many outlines made in succession of this
same lorica, to show how identical they all are in character. The
large drawing or diagram of some well-known forms of diatoms
is a tour de force, and here the effect would be better, or easier
got, by copying some moderate-sized prism outlines, by means of
the pantograph ; but the drawing as it stands really was executed
under the Microscope; the paper was laid on the ground with a
bright light thrown upon it, the Microscope was well raised over the
edge of the table. The image—enormously amplified—got from
a 1/6 objective, was projected by the prism, and was traced upon
the paper by the aid of a pencil ; which pencil might be said to be
some 5 feet long, inasmuch as it was formed by a crayon tied
firmly on a joint of a fishing-rod. ‘That the outline so traced was
a bit “shaky,” and needed “ mending” may well be imagined, but
the reparation has, I think, not been made at the expense of the
characteristic curves of the various diatoms. I am sure the relative
size of each may be depended on, though I must own to depicting
the largest and boldest specimen of P. angulatum I could lay my
hands on.
After this much of preamble, permit me to name the various
forms of drawing appliances or prisms from which to make a
selection ; all of them have some merit, and some of them, as I
trust I shall be able to show, are pre-eminently useful. First
come “steel disk” or “ neutral-tint” glass reflectors; then prisms
proper, by Wollaston, Gundlach, Beck, Oberhauser, Zeiss, Nobert,
Abbe, Nachet, and Schréder. They may be classed thus,
Wollaston, steel disk, and glass reflector can only be used when the
Microscope is placed horizontally—a position which is always a
more or less cramped one for the observer, and which is all but
impossible to adopt in connection with dissections, and indeed with
most objects mounted in fluid and more or less free to move in the
cells. The prisms of Beck, Gundlach, Zeiss, and Schréder are avail-
able when the Microscope is set at the usual observing angle.
The prisms of Oberhauser, Nobert, Abbe, and Nachet can only
be employed when the Microscope is placed in a vertical position ;
the image is projected a few inches to the right-hand side of the
Microscope, and falls on a sheet of paper fixed to a 2 ft. drawing
board, so that tle point of a peasit which is held in the right
hand, is in a convenient position to trace the outline of the
projected image.
I will now proceed to describe the special qualities which some
of these prisms have as adapting them for particular purposes.
3A 2
700 Transactions of the Society.
The “reflectors” and the “Gundlach” will be found in use to
“invert the image”; this inversion is very troublesome, and if not
well understood, and met with certain devices, is apt to lead the
draughtsman into endless confusion. In practice when you use
one of these inverters you are compelled to sketch from the one
side of a slide of objects, and to fill in detail from the other, and as
a clever writer has pointed out with respect to this arrangement,
“the back and the front of an object are not always alike.”
The image got by a Wollaston prism is so excellent that this
instrument would always be used, were it not that the setting of the
Microscope in a horizontal position, the re-arrangement of the
light, &c., the dependent position of the eye while drawing, the more
or less cramped position, and other difficulties with respect to the
slipping of fluid preparations oblige one to employ more convenient
though perhaps in other respects less satisfactory appliances. Of
the prisms used at the ordinary observing angle of the Microscope,
Gundlach’s, as I said, inverts the image, and I am sorry to say that
the Zeiss prism, though it is quite satisfactory in my hands, in ,
most respects, projects the image so far forward as almost to come
upon the stand of the Microscope, and so practically cramps the
position of the drawing paper or board; I therefore seldom use
it. I lke the Beck prism, and I make perhaps more use of it
than of any other, as the light transmitted, the field, and the sight
of the pencil are all satisfactory.
The Schroder prism just invented has several points of
excellence, which will win appreciation. It shares with the
Wollaston the rare quality that the pencil is seen with equal
distinctness in all parts of the field, and that there is no apparent
change in the position of the point of the pencil from imvolun-
tary oscillation of the head of the draughtsman. I am only sorry
to be obliged to say, that I find the usefulness of this neat
little instrument is much limited by the very small amount of light
it transmits from the object under the Microscope; entailing the
condensation of such a body of light by ‘‘racking up,’ when
anything like a high power objective is used, as rather to strain
the vision and make anything like detail too much a matter of
guess. I am encouraged to hope that this condition may be
susceptible of modification, and in such case the Schréder prism
would not leave much to be desired.
I may just say, that while not appreciating the Abbe prism
used for the purpose for which it was constructed, I recognize a
most valuable quality which it possesses, for copying drawings and
engravings of small area, either of the size of the original or with
a slight magnification at will. I think I can see a considerable
future for this prism in certain branches of the fine arts.
On Drawing Prisms. By Dr. Anthony. 701
For the Microscope placed vertically, I will only call attention
to one drawing appliance, viz. the “ Nachet hooded prism,” which
you will see I have placed on the ocular of a Microscope in the
usual position for sketching. Looking through this prism the
image in the Microscope will be seen projected some 5 in. on to
the drawing-board placed on the right-hand side. As a prism
this has all the advantages and the faults of the class to
which it belongs; a very prominent fault being the all but total
loss of sight of the image of the pencil when an attempt is made
to follow the outline of an object seen between the centre and the
outside edge of the field of view—calling the outside that which is
apparently farthest away from the microscope-body.
If the drawing-board is placed flat upon the table, you will find
that your drawing so made by the Nachet will be much distorted.
A good article in our Journal * set me off to experiment on this
distortion, and how to get rid of it. I show the satisfactory results
arrived at. The boy’s head—a cutting from ‘ Punch ’—has been
copied twice, in the left-hand picture the drawing-board was flat
upon the table. The eye will detect the distortion in a moment,
in the head being far too deep from front to back. The right-
hand image—taken with the board raised 2 in. at its right-hand
end—shows not a trace of distortion. Here is a still more severe
test: these (fig. 120) are copies of the circles in Méller’s smaller
Fic. 120.
“typenplatte” under the same conditions as to position of drawing-
board. The right-hand picture is shown by the dotted circle struck
by the compasses to have lost the distortion, which is painfully
evident in the one on the left-hand side.
* Vol. ILL. (1883) p. 560.
702 Transactions of the Society.
In this drawing (fig. 121) of the lines of a fine stage-micro-
meter, with drawing-board horizontal and inclined, all appreciable
Fig. 121.
distortion has been got rid of by the simple device of raising
the right-hand extremity of the drawing-board. Well, this dis-
tortion being eliminated, and the loss of sight of the pencil under
certain conditions condoned, we must recognize this prism of |
Nachet as being exceedingly useful and convenient in practice, it
being so hinged upon the collar which clasps the ocular, that the
optical part can be thrown back like a hood, so as to give a clear
view of detail through the ocular only, and the prism can be tilted
forward again at will to resume the sketching of outlines with no
fear of loss of coincidence with its former position. A tinted glass
which can be interposed between the object and pencil respectively,
helps to make the Nachet hooded prism a great favourite of mine.
Speaking of this “light-moderator” brings me to the point
that one of the great secrets of success in prism drawing from the
Microscope is the equalization or balancing of light from object
and pencil. The best effect by far is got by two lamps. Where
light from the paper is too glaring, as will often happen with
the Schroder prism used in daylight, the half-shadow of a curtain
allowed to fall upon the paper conduces wonderfully to ease in
sketching. I have intimated that with the Schréder prism you may
move your head as much as you like, but not so with the other
little optical appliances, and this keeping the head steady is as
difficult as it is wearisome. Failing an appliance something like
a photographer's “head-rest,” let me suggest a substitute in a
microscope-box, in the position that the left elbow can rest upon it,
when the outspread thumb and fingers placed against the forehead
will be found to keep the head of the draughtsman fairly steady.
A small black velvet curtain, so hung ag to touch the microscope-
tube just below the ocular, will be found to aid materially in
distinctness by cutting off diffused light. You want to see all you
can of your object, but make up your mind you will never see
On Drawing Prisms. By Dr. Anthony. 703
anything like the amount of detail through a prism which you do
through the unarmed ocular.
My conviction then is, that the prism has done very much—and
indeed all it can do—in enabling you to get rapidly and correctly
as a sketch the outlines and salient points of your object under
examination, to which your more or less artistic eye will have to
supply the detail.
Now to sum up the evidence for the most useful forms of
prism :—
At the usual observing angle of the Microscope, and when the
object is fairly transparent, Beck or Schréder will do good work,
but where there is opacity, then Gundlach is to be preferred, in
spite of its inverting the image.
When the Microscope can be placed horizontally, and the
objects are suitable, Wollaston’s prism gives results of pre-eminent
beauty.
With the Microscope vertical, Nachet’s hooded prism, I think,
stands alone for making copies of almost all objects susceptible of
magnification, and it is especially good when dissections are made
under the Microscope by aid of an “rector,” as the convenient
tilting backwards and forwards of the prism
allows outlines to be traced, and then dis- Fig, 122.
section to be resumed with the most charming =
facility.
This review of prisms has been a mere
outline, but it has taken up all the time I
could venture to occupy. While striving to
criticize fairly, and placing most stress upon
practical points, I have ventured to show
what a long and assiduous use of the prism has effected in my
hands: permit me to end with the hope that it may do still more in
ours.
N.B.—Fig. 122 is a woodcut of the Beck prism, which I
believe has not previously been figured.
704 SUMMARY OF CURRENT RESEARCHES RELATING TO
SUMMARY
OF CURRENT RESEARCHES RELATING TO
ZOOLOGY AND BOTANY
(principally Invertebrata and Cryptogamia),
MICROSCOPY, &c.,
INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.*
ZOOLOGY.
A. GENERAL, including Embryology and Histology
of the Vertebrata.
Embryology of the Sheep.j —Dr. R. Bonnet has investigated the
earlier stages of development in the sheep embryo.
His positive results commence from the twelfth day after impreg-
nation. Embryos of this age showed round, uniformly bilamellar,
germinal vesicles, with a round, bilamellar, embryonic disk of about
-25 mm. in diameter. The epiblast of the disk consisted of two or
three layers of cylindrical cells continuous with the flattened ecto-
blast of the vesicle. The entoblast formed a single distinct layer of
cells, distinguishable into two classes, according to position, viz. :—
1. Ovoid cells, beneath the disk.
2. Flat cells, forming a retiform membrane, lining the vesicle
generally.
The ovoid cells form “the entoblast of the (future) digestive
tract,” the flat peripheral cells “the entoblast of the yolk-sac.”
On the thirteenth day there appears in the vesicle, peripherally
to the disk, a formation of mesoblast in the vesicle. No trace of such
a mesoblastic growth is found at this stage in the disk.
Within the disk, mesoblast is formed a little later in a twofold
manner. Beneath what eventually is the primitive groove there is
formed an ectoblastic “thickening” (Knoten). From this is developed
the “central” or “ectoblastogenous” mesoblast, which remains in
direct and intimate connection with the ectoblast axially. The
“peripheral ” or “‘ entoblastogenous” mesoblast arises as a peripheral,
* The Society are not to be considered responsible for the views of the
authors of the papers referred to, nor for the manner in which those views
may be expressed, the main object of this part of the Journal being to present a
summary of the papers as actually published, so as to provide the Fellows with
a guide to the additions made from time to time to the Library. Objections and
corrections should therefore, for the most part, be addressed to the authors.
(The Society are not intended to be denoted by the editorial ‘‘ we.”)
+ Arch. f. Anat. u. Physiol. (Anat. Abtheil.) 1884, pp. 170-230 (3 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 705
lenticular thickening of the entoblast of the digestive tract, and its
cells wander or are thrust in, centripetally, to meet the centrifugal
growth of the ectoblastogenous mesoblast. Very soon, however, the
production of entoblastogenous mesoblast is observed to take place, not
merely at the periphery, but over the whole surface of the entoblast
of the digestive tract. Dr. Bonnet concludes that the cells of the
mesoblast are to be regarded as mesenchyma in the sense of the
Hertwigs.
The primitive thickening of the ectoblast grows caudally to form
the primitive streak, whilst the primitive concavity which is hollowed
out in it elongates caudally in a similar manner to form the primitive
groove.
By the fourteenth day there is a cranial process of the primitive
streak, the first “ rudiment of the ectoblastogenous chorda.”
The formation of the ccelom in the sheep commences peripherally
from the disk in the outlying tract of mesoblast, and progresses
centrifugally, its proximal limit being formed by the very distinct
mesoblast-forming border of the entoblast of the digestive tract, now
underlying the growing disk.
The author has found a canal piercing the cranial process of
the primitive streak, and placing in (temporary) communication
(1) the surface of the epiblastic thickening from which the neural
canal is later formed, and (2) the digestive cavity. This canal he
identifies with Balfour’s neurenteric canal.
The first beginning of the blood-vessels was discovered in the
proximal region of the coelom, external to the embryo, and was seen
to arise contemporaneously in both layers of the mesoblast at this
point, developing centrifugally at a later period. As both layers of
mesoblast are, according to Dr. Bonnet, entoblastic, arising in the
first instance at the border of the entoblast of the digestive tract,
there is proof of the “indirectly entoblastic origin of the rudiments
of the blood-vessels.”
Dr. Bonnet promises a further paper on the further development
of the sheep’s embryo.
Development of the Generative Organs.*—O. Cadiat has an
important memoir on the development of the generative organs in the
embryos of the sheep and of man. The results are as follows :—
The internal always appear before the external generative struc-
tures. The cloacal cavity, which is formed early, commences to divide
in embryos of 8 mm. long into an intestinal and genito-urinary portion ;
but at the lower end of embryos of this age the two are still in com-
munication. When the embryo has attained to 1 cm. in length the
separation has advanced somewhat further back, but at the level of
the caudal extremity there is always a small common cloacal cavity.
In embryos a little older (12 mm.) the genital become partly sepa-
rated from the urinary passages; it is not until much later (embryos
of 6-7 cm.) that the separation between the intestinal, genital, and
urinary tubes is complete.
* Journ. Anat. et Physiol., xx. (1884) pp. 242-59 (4 pls.).
706 SUMMARY OF CURRENT RESEARCHES RELATING TO
The prostate glands are stated by Kolliker to make their appear-
ance at about the third month in the human embryo; in reality,
they appear somewhat earlier, about the second month; in a
previous investigation carried out in conjunction with M. Robin, it
was found that the prostate glands form a system entirely inde-
pendent of their ducts and of the ejaculatory canals; and the present
research confirms this idea; the prostate also is not connected
with the urinary apparatus, as it was said to be by Virchow, but
with the genital system; it is comparable to the glands of the
urethra in the female; the entire urethra in the female is conse-
quently homologous with the prostatic portion only of the male
urethra, while the penial portion, including Cowper’s glands, cor-
responds to the vulva in the female. =
The external genital organs are fully formed at a somewhat
earlier date in the male than in the female; at three and a half
months they are very nearly complete in the male, while in the female
at this period there is still a slit uniting the urethra with the vagina ;
a complete separation is accomplished after four months.
Spermatogenesis,*—MM. Swaen and Masquelin have published
their very interesting observations on the developmental history of
spermatozoa, in continuation of the work of Lavalette St. George.
To understand the work of the later observers, it is necessary to
recapitulate St. George’s conclusions. They are as follows :—Sper-
matozoa originate in special cells, very similar to young ovules,
which may be called spermatogonia. These elements multiply and
form groups of small cells, spermatocytes, which remain grouped
together so as to constitute <permatogems. At the periphery of the
spermatogems a certain number of spermatocytes are modified so as
to form a membranous envelope, a cyst (amphibians and insects).
In other cases (Selachians), a single spermatocyte is modified at the
base of the spermatogem and forms the basilar cell. In mammals,
on the other hand, the spermatogem developes neither a cystic
membrane nor a cystic basilar cell. Itis the spermatocytes which
are transformed into spermatozoids.
In addition to these elements there occurs a second kind of cell,
forming a more or less complete envelope for the spermatogonia.
These follicular cells play only a very secondary part in sperma-
togenesis, eventually disappearing.
MM. Swaen and Masquelin conducted their researches on the
testicles of Scylliwm catulus, the salamander, and the bull.
In Scyllium, the seminiferous ampulle of the testicle (cf. Graafian
follicles) contain groups of two kinds of cells, (1) the central sper-
matogonium or male ovum, a large nucleolo-nucleate cell partly in
contact with the adjacent connective tissue, partly bounded by (2) the
smaller, oval or irregularly shaped, follicular cells. As the “male
ovule” multiplies (by indirect cell-division), the follicular cells also
multiply and force their way inwards between the resulting daughter-
cells of the spermatogonium to finally form a bilamellar body
* Arch, de Biol., iv. (1883) pp. 749-802 (5 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 707
composed peripherally of the latter cells and internally of the
follicular cells.
The two classes of cells remain throughout perfectly distinct, and
Semper is mistaken in thinking that male ovules can be formed from
follicular cells.
Cell-division of the male ovules eventually forms bicellular columns
of radiating cells. These columns are the spermatogems, of which
the component cells are the spermatocytes. Each spermatogem is
proximally capped with a follicular cell, generally crescent-shaped.
When each spermatogem consists of six cells this follicular cell
makes its way centrifugally between the columns, and attaches itself to
the distal end of the spermatogem as the so-called “ basilar nucleus ”
(really a complete and distinct cell).
When this stage has been reached, the remaining follicular cells
atrophy and further multiplication takes place in the spermatocytes,
the resulting rows of cells (nematoblasts) arranging themselves with
reference to the axis of the spermatogem (or nematogem, as it may
now be called) much as the plumules of a feather with reference
to the rachis.
A caudal cavity is now formed internally in each nematogem,
and into this space protrude the “tails” of the resulting spermato-
zoids. The nematoblasts in their development become rectilinear,
and their distal ends eventually form a parallel series, capped by the
basilar nucleus. The head of the nematoblast is composed both of
nucleus and of cell-protoplasm. The appearance of the nematogem
is that of a cone of tapering filaments.
As regards the “ problematic body,” nothing new was observed.
Eventually the basilar nucleus forms a simple tube surrounding
the “sheaf” of spermatozoids, and it is probably by its contractions
that these latter are finally expelled.
In the salamander the ampulla show a cavity, and the follicular
cells form an investment for the male ovules. Multiplication and
other phenomena occur much as in Scylliwm.
In mammals the true male ovules are the small parietal cells
considered as follicular by Lavalette. These male ovules behave in
mammals much as their counterparts in Selachians, &c., except that
of the two first products of their division, the one remains inactive
for a certain time (inert male ovule), whilst the other (active male
ovule) multiplies by division toformaspermatogem. This peculiarity
of mammalian spermatogenesis is due to the continuous production
of spermatozoids in the same seminiferous tube.
In conclusion, MM. Swaen and Masquelin institute the following
conclusion between cell-development in testicle and ovary :—
1. In the ovary, the ovule little by little assumes considerable
proportions, the follicular cells multiplying actively to form a con-
tinuous envelope, and in some cases to effect the expulsion of the ovule.
2. In the testicle, the ovule forms a number of little cells which
eventually become spermatozoids. The follicular cells multiply to
only a slight extent; more commonly they increase in size (Sela-
chians and salamander).
708 SUMMARY OF CURRENT RESEARCHES RELATING TO
Factors of Sexuality.*—K. Diising commences by discussing the
correlation of the organs, and reminds us of the familiar fact that
agriculturists are in the habit of removing the genital organ from
those individual cattle that they wish to fatten. It is next pointed out
that in nearly all cases where organs disappear, as for example in
parasites, the reproductive apparatus is always retained, while, on the
other hand, in sterile hybrids there is a marked development of the
organs which preserve the life of the individuals.
With regard to the proportional relations of the sexes, we have some
statistical observations; to these the author now adds some consider-
ations from the point of view of the doctrine of natural selection, and
he points out that the numerical supremacy of one sex may be of
considerable advantage in the development of a large progeny. He
thinks, further, that it is possible to demonstrate mathematically that,
where there is an abnormal relation of the sexes, an animal which
produces a large number of the kind of individuals that are wanting
will leave more descendants than one that does not do so. This
peculiarity will, in time, be confirmed by natural selection. In
illustration of this reference may be made to what seems to be a
statistical truth ; late fertilization of women tends to the production
of males, and, in all circumstances, the first-born are, in the majority
of cases, boys. Further, the author believes that statistics show
that after a war there is a large preponderance of male babes.
Where, among cattle, demands are largely made on an individual
bull, the majority of his progeny are males, and this is because young
spermatozoa tend to produce males; this view of the different value
of spermatozoa of different ages has the support of so high an authority
as Prof. Preyer. Reduced to a general law, the results may be thus
enunciated: the larger the want of individuals of one sex, the more
frequently are their genital products required, and, therefore, the
more frequently do the minority produce young of their own sex.
The investigations of Thury have shown that young ova tend to form
progeny of the female sex, while delayed fertilization leads to the
production of males; the calves of the earlier stages of the rut are
more frequently females than those of the later.
The indirect causes which are equivalent to an absence of indi-
viduals are (a) insufficient nutrition ; the effect of this is seen in the
the fact that a well-fed cow served by a starved bull always produces
males, and inversely. In other words, there is a close connection
between nutrition and reproductive capacity. (@) Difference in age.
Every individual at the time of its highest reproductive capacity tends
to produce its own sex; and the preponderance of males is greatest
when the male is considerably older than the female. This law was
discovered by Hofacker and Sadler, and is supported by the 58,000
cases reported on by Goehlert and Legoyt.
We come, then, to this conclusion: Animals have by adaptation
acquired the power, in the presence of abnormal sexual relations, of
producing more individuals of the sex of which there is a want; and
the same balance is maintained by the same methods when there are
* Jenaisch. Zeitschr. f. Naturwiss., xvi. (1883) pp. 428-64.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 709
‘at work indirect causes which are equivalent to a want of the indi-
viduals of one sex.
In another sense the influence of nutriment is of the greatest
importance; notwithstanding the fact that a starving animal may
reproduce itself numerously, the progeny are feebler than those of
one which only produces as many as, under these conditions, can live
and thrive. Surplus nutriment leads to the production of a stronger,
and insufficient food to that of a weaker progeny. Domesticated.
animals breed earlier, and are more fruitful than the wild ; townsmen
and sedentary people more than countrymen who take much hard
exercise. More children are conceived in summer than in winter ;
and in Scotland, according to Haycraft, the maximum of conceptive
capacity is simultaneous with that of the thermometer. Birds, bats,
and insects breed less numerously than fishes, and especially than
parasites who use up little or no force in movement.
The differences we observe between males and females are easily
explained when we consider the very different parts that they play in
the physiology of reproduction; it must always be remembered
that it is the office of the female to produce the material out of which
the embryo is built up.
The author concludes by reasserting his conviction that it is in
the principle of natural selection that we must look for the explana-
tion of the differences between the sexes.
Rudimentary Placenta in Birds.*—One of the principal dis-
tinctions between the Mammalia and the lower Vertebrata has been
hitherto supposed to be the possession by the former of a placenta.
M. Duval has, however, come to the conclusion that this structure is
not exclusively confined to the Mammalia, but that it also exists,
though in a rudimentary form, in birds.
The allantois in passing inwards into the pleuro-peritoneal cavity
does not become attached to the amnion or to the umbilical vesicle,
but joins the chorion, becoming fused with it; it ends by forming
a sac which incloses a mass of albumen; into this sac the villi of
the chorion project, and an organ is thus formed which is completely
analogous to the placenta of the Mammalia; the different form of
the organ in birds and in mammals is evidently owing to the dif-
ference between the oviparous and viviparous method of reproduction ;
the villi of the chorion in Mammalia are attached to the body of the
mother, while in birds the necessities of the case demand that they
should be developed upon the opposite side of the chorion and attach
themselves to the nutritive albumen. It is, however, quite intelli-
gible that in an ovoviviparous vertebrate, where the egg has a thin
membranous shell, the placentoid organ should become attached
to the internal surface of the oviduct. This placenta of birds is
therefore a rudimentary organ which enables us to understand how
the placenta of the Mammalia may have originated. A physiological
difference between the placenta of birds and of Mammalia is that in
* Journ, Anat. et Physiol., xx. (1884) pp. 193-201 (4 pls.). See also this
Journal, ante, p. 360.
710 SUMMARY OF CURRENT RESEARCHES RELATING TO
the former the exchange of gases takes place, of course, by the outer
surface, so that the two functions of respiration and nutrition are
relegated to two different portions of the placenta, while in mammals
they both take place on the outer surface of the organ.
Permanence of larval conditions in Amphibia.*—As a general
rule the Amphibia when mature cease to breathe by means of gills; the
latter disappear and respiration is carried on solely by means of the
lungs. There are, however, a number of cases known, and they are
increasing daily, where branchial respiration is carried on for a
longer or shorter period of the life of the adult. LL. Camerano has
lately paid some attention to this subject, and has investigated a
certain number of these Amphibians, paying special attention to the
dimensions of the adult animal, its organs of reproduction, colour,
alimentary system, lungs, and nervous system. The period during
which branchial respiration continues varies in different Am-
phibia; the shortest known to him is in Salamandra aitra, the
longest in Proteus anguineus, the axolotl, and Triton. In almost all
the Amphibia of Europe cases are known of an abnormally short or
abnormally long “ branchiate-period.” These may be divided into
two classes: (1) those instances of simple hibernation, where the
animal has not had time in a single summer to attain maturity ; and
(2) other cases where the branchie remain functional for several years.
In this respect, however, the Urodela differ from the Anura; the
former are influenced by local conditions, such as food, presence of
floods, &c., which render it necessary for them to continue an aquatic
life though the development of the other organs of the body goes on
quite as rapidly as in individuals that have adopted a terrestrial life.
In the Anura, on the other hand, the permanence of the branchie for
several years is accompanied by an incomplete development of other
structures. Such cases are, however, rare, and are not, as in the
Urodela, a modification owing to local causes, but are a reversion to
an ancestral condition.
The Amphibia as a class are clearly most nearly related to the
fish, and the occasional permanence of a branchiate condition is the
best proof of this relationship; it is, however, none the less possible
that branchie were acquired later, and that the Amphibia were primi-
tively land-dwellers, assuming the branchiate condition as a“ retrograde
metamorphosis” by the adoption of an aquatic life. Keeping in view
this possibility it is easy to understand how by artificial interference
with the biological conditions, the Amphibia may pass from a
branchiate to a pulmonate respiration and back again.
The old division of Perennibranchiata and Caducibranchiata is
therefore unphilosophical: the real proof of the adult condition of an
Amphibian is the maturity of the reproductive organs, and its branchi-
ate or pulmonate condition must be neglected since it is merely an
instance of dimorphism dependent upon the influence of the environ-
ment.
* Mem. R. Accad. Sci. Torino, xxxy. (1883) 64 pp. (2 pls.). Natuiforscher,
Xvil. (1884) pp. 273-4.
ZOOLOGY AND BOTANY, MICROSOOPY, ETC. 7p a
Embryo Fishes.*—The Bulletin of the United States Fish Com-
mission contains a series of articles upon various matters connected
with the development of fishes, embodying the results of the investiga-
tions of Mr. J. A. Ryder during the year 1882.
The mode of absorption of the yolk of the embryo shad differs in
the absence of a vitelline circulation from that which obtains in
Tylosurus (Belone), Fundulus, Esox, and Salmo. The great mass of the
yolk in the shad embryo consists of coarse irregular masses of very
clear protoplasmic matter, separated by a protoplasm which is opti-
cally different. The covering of the yolk is a palish amber-coloured
layer, quite different from the clear body of the yolk, and usually
thicker at the end next the heart. The intestine lies in a longitudinal
furrow on the dorsal aspect of the yolk-sac, and is never connected
with it in this species. The yolk-sac is surrounded by a space
filled with serous fluid. This space is capacious anteriorly, between
the heart and the yolk, and this part is identified by the author
with the segmentation-cavity. The delicate pericardial membrane
that separates this cavity from the pericardial space may, possibly, be
perforated. In Tylosurus the two cavities are certainly connected.
The heart opens freely into the segmentation-cavity, and the appear-
ance presented is that its persistent pulsation breaks up the yolk-
substance into small spherules, sucks them out of the segmentation-
cavity, and carries them into the body of the embryo. The corpuscles
develope on the surface of the outer yolk-layer, and after a while drop
into the serous fluid, appearing likethe white blood-cells of human blood.
As development proceeds, the yolk-sac becomes pointed in front, and
the external layer becomes thicker, while the pericardial membrane
becomes funnel-shaped to fit the anterior part of the yolk-mass. Before
the final disappearance of the yolk, the liver of the young fish becomes
more developed, and the portal vein makes its way over the dorsal
aspect of the yolk towards the venous end of the heart. As the
peculiar amber-layer around the yolk persists to the last, it is probable
that the central clear portion is transformed gradually into it.
This is the history of the yolk-mass after the embryo is hatched,
but as it grew in size before hatching, yolk-absorption must have
taken place before the heart was sufficiently developed to be an active
agent in the process. This must be by intussusception, and in the
amber yolk-covering it is undoubted that a process of cell and blood-
cell differentiation takes place. Mr. Ryder concludes that the hypo-
blast of Gensch, said by that investigator to be the source from which
the blood is derived, is the equivalent of the amber yolk-covering of
the shad, and not the true hypoblast. This amber layer is a tempo-
rary structure, which disappears entirely, and does not enter into the
formation of any organ or membrane. The serous cavity around the
yolk in the shad represents the body-cavity, and the outer covering
of this, though only 1/2000 of an inch in thickness, contains epiblast,
mesoblast, and hypoblast.
* Bull. U.S. Fish Commission—Observations on the Absorption of the Yolk,
the Food, Feeding and Development of Embryo Fishes, &c., pp. 179-205. Amer.
Natural., xviii. (1884) pp. 395-8.
(1 SUMMARY OF OURRENT RESEARCHES RELATING TO
There is practically little difference between the modes of yolk-
absorption in the chick and in the fish.
The author brings forward facts to prove that there is between
ova, even of allied genera, considerable differences, and that at no
stage is there a positive identity.
The mechanical construction, as it may be termed, of ova affects
the course of their development. The Teleost ovum has a relatively
enormous yolk, which must be included by the blastoderm in order
to be absorbed, and this relatively large yolk has much to do with
the difference observed between its development and that of a Mar-
sipobranch or Amphibian. The eggs of the Salmonide have an
abundance of oil-drops in the vitellus, especially just under the
germinal disk. These by their buoyancy keep the disk constantly
directed upward. The cusk, the crab-eater, Spanish mackerel, and
moon-fish have eggs which are buoyant from the possession of a
single large oil-sphere situated almost exactly opposite to the germinal
disk, and thus keeping it face downwards—just the reverse of what
occurs in the Salmonoids. Even after hatching, the young are at first
unable to right themselves on account of the presence of the oil-drop.
The cod ovum has no oil-drop, yet floats with the germinal disk
downwards. That of Morone Americana (white perch) is adhesive
and fixed with a very large oil-sphere, which keeps the disk on the
lower side of the vitelline globe. The shad egg is non-adhesive, and
heavier than water, and the germinal disk has a constant tendency to
arrange itself at the side of the vitellus as viewed from above, though
there is no oil to influence it. In Fundulus and Syngnathus the oil-
drops appear uniformly distributed. The number of proto-vertebre or
primary somites differs so much that while Tylosuwrus has so many as
seventy-five pairs, Alosa has only eighteen to twenty. ‘The author
ventures this bold remark: ‘‘ When our knowledge is more complete,
we shall perhaps be able to distinguish the species apart by the eggs
alone, just as botanists have used the characters presented by seeds to
distinguish plants.”
Development of Viviparous Minnows.*—J. A. Ryder describes
the development of viviparous minnows, and particularly Gambrusia
patruclis B. and G. 'The young fish develope within the body of the
female parent, and within the follicles in which the eggs themselves
are developed. The follicles, which are covered with a rich network
of fine capillary vessels, assume the office of a respiratory apparatus,
by which the gases are interchanged between the embryo and the
parent fish. This follicle also acts as an egg-membrane, being
actually perforated by a round opening (“follicular pore”) which is
analogous to the micropyle of the ordinary fish-egg. The arrange-
ment of the follicles of the ovary within the body of the female is
described, and the peculiar differences between the two sexes in the
arrangement of the viscera pointed out. The fibrous bands, which
act as supports or stays to the basal portion of the anal fin of the
male, which is modified as an intromittent organ, are also described.
* Science, iii. (1884) p. 769.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 713
The great difference in the sizes of the sexes is also referred to, the
female weighing over six times as much as the male.
Formation of and Reactions of Nuclei.*—C. Frommann finds
that the application of acids to nuclei of non-amceboid cells does not
result at first in a great change in the yellowish granules of the
protoplasm, but that, after the acids have acted for some time, they
become pale and can no longer be accurately distinguished from one
another, and the nucleus appears to be surrounded by a distinct
membrane. With amceboid cells the action of acids results in the
appearance of a firm stroma and a firm more complete investing
membrane; from the material of the protoplasmic granules new
nuclei as well as separate longer filamentar structures are formed,
or granules only are formed, and the protoplasm becomes clearer and
more homogeneous. It must be borne in mind that we have here to
do with artificial products. The author criticizes the views of Robin,
and points out that structures, which we are bound to compare with
nuclei, are to be found in the living colourless blood-corpuscles ; this
has been proved by Stricker for non-defibrinated, and by Frommann
for defibrinated blood, and Flemming speaks very positively as to the
presence of nuclei in living leucocytes, whether in or out of the
vessels of the larve of the salamander.
If a homogeneous body, either spontaneously or after the action
of chemical or physical reagents, differentiates into a formed and a
homogeneous substance, the phenomenon may be explained by the
supposition that both bodies were present, but had the same re-
fractive index, or by supposing that the apparently homogeneous
body was really so, and that the appearance of formed elementsis due
to a differentiation of its substance into elements which are more
highly refractive, and a clear substance which fills up the interspaces.
The author is inclined to accept the latter view as applying to what
obtains with nuclei, and supports it by various considerations. Ex-
periments with salt solutions show that, after the fusion of the whole
mass of the grains and granules with the nucleus, the whole structure
thus formed becomes converted into a nucleus with sharply defined
stroma and firm investment, so soon as spring or distilled water is
added to the preparation. Various other experiments are detailed,
the study of which is a matter of great importance for those who are
making observations or experiments in connection with the phenomena
exhibited by nuclei.
Indirect Nuclear Division.t—E. Strasburger commences an essay
on the subject of the controversy with regard to indirect nuclear
division by an account of some specimens of the embryonic sac of
Fritillaria imperialis, which had been prepared by Herr Heuser. He
concludes from his numerous observations that it is very probable
that in all typical processes of the indirect division of the cell-nuclei
of plants there is a stage in which the segments of the nuclear
filament divide longitudinally. This process is not, however, always
* SB. Jenaisch, Gesell. f. Med. u. Naturwiss., 1883 (1884) pp. 4-16,
+ Arch. f. Mikr. Anat., xxiii. (1884) pp. 246-304 (2 pls.).
Ser. 2.—Vo.. IV. 3B
714 SUMMARY OF CURRENT RESEARCHES RELATING TO
found to be associated with the same definite arrangement of the
segments in the nucleus, and it may either precede or succeed the
arrangement of the segments into the nuclear plate.
If we compare what is now known as regards plants with the
results of studies on the division of the nuclei of animals we find
that, with one exception, there is really no important difference
between them. The investigation of plants shows that the spindle-
shaped fibres almost certainly arise from compressed cytoplasm. The
whole framework of the nucleus is to be found in the filamentar coils,
while the nuclear cavity is only filled by homogeneous nuclear fluid.
The whole mass of spindle-shaped fibres have their origin in the
cytoplasm.
The difference in the way in which cell-division is completed is a
point of distinction between animals and plants, but it does not obtain
in the lowest forms of either kingdom. The formation of the con-
nective filaments in the separation of the cell-body is a distinctive
characteristic of plants; but, notwithstanding this, the result of cell-
division is the same in both plants and animals.
In both we find that in the “ prophases” of nuclear division cyto-
plasm is collected at the future poles of the cell-nucleus; this
phenomenon is often very striking in animal-cells, and is especially
well marked in ova. The nucleus becomes provided with two
radiating systems, even before any dicentric arrangement can be
detected in the cell-nucleus. The observations which the author has
made lead him to think that the spindle-shaped fibres derived from
the cytoplasm have a directive influence on nuclear division ; the
frequently simultaneous division of nuclei in multinucleated cells may
be easily supposed to be due to this influence and the surrounding
cell-plasma.
Strasburger thinks that some of the aberrant forms of division
noted by Flemming may be explained by what he has seen in plants.
The tub-shaped figures which become apparent during the arrange-
ment of the segments in the testicular epithelium of the salamander
call to mind what was seen in the embryo-sac of Fritillaria, and
suggests that an explanation is to be found in the divarication of the
daughter-segments on one side, and their approximation to one another
on the other. In the red blood-cells of Salamandra the cell-nucleus
becomes considerably enlarged during the development of the fila-
mentar coil, and a large amount of cell-substance is taken up into the
nuclear figure. If the spindle-shaped fibres form only a small figure
in the cell, it would be clear that all the cytoplasm was not used up
in forming this figure, and we should have a case similar to that seen
in the pollen-mother-cells of Fritillaria persica, where in the first act
of division granular cytoplasm is found between the spindle-shaped
fibres.
The ideas now derived from a study of animals and plants cannot be
directly applied to the Protista, where the separate parts of the cell-
body often undergo great changes and become adapted to new functions;
we must greatly increase the number of our observations before we
can hope to arrive at generalizations of universal value.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 715
The function of the complicated nuclear division appears to be
that of dividing the nucleus into two completely equal halves; in the
first segmentation the parts are often very unequal in size, and if,
as Heuser supposes, there are several different substances in the disks
of the microsomes longitudinal division would be the safest means
for distributing the substances equally to the two daughter-nuclei.
It is quite clear that the nucleus has a nutrient function for the cell,
though we do not yet know what its character is. In the internodes
of the Characez we see the nucleus increasing in proportion to the
mass of the increasing cytoplasm, although here cell-division does not
accompany nuclear division; here indeed direct division of the
nucleus (by constriction) takes the place of indirect division.
Nucleus of the Auditory Epithelium of Batrachians.*—The
results of J. Chatin have a double interest, as affording us more
complete information as to several points in the comparative histology
of the auditory epithelium, and as bearing on the structure of the
nucleus.
The study of the epithelial layer which invests the labyrinths of
Batrachians demonstrates a close relationship between the sustaining
and sensitive elements; they are intimately connected, and they
undergo the same kind of modifications. What is true of Batrachians
is true also of other vertebrates ; in the Mammalia, for example, there
are auditory rods and ciliated cells, but between the two all inter-
mediate stages are to be made out, and this even at some single
int.
As to the intranuclear corpuscles the author finds that, so soon as
they have acquired their definite characters and become grouped in a
plexus they are all perfectly identical; there is no trace of any
nucleolus. In insects, Chatin has noted the inconstant character of
the nucleoli, and Klein, working at certain glandular elements of the
Batrachia, likewise bears witness to their absence.
Epidermis of the Chick.t—C. Frommann has examined the
epidermis of the chick during the last week of its stay in the shell,
and finds in it granular cells and net-cells; the former are rounded
or oval and contain granules which are fused into cords of various
forms; these are connected with one another by filaments of various
degrees of fineness, which traverse the delicate spaces left between
them ; here and there, however, there are larger spaces. In neither
case have the spaces any special wall. The body of the net-cell is
traversed in all directions by a wide-meshed network ; part contains
neither nuclei nor any aggregations of cell-substance, while in other
parts the nodal points have nuclei. On the whole, the characters of
the cells of the epidermis are the same as after the period when the
chick leaves the egg. Certain differences are presented in the parts
of the skin which are feathered, for there is there ordinarily a layer
of small granules imbedded in a pale, finely granular substance, in
which nuclei are either completely absent or are irregularly scattered
* Ann. Sci. Nat. (Zool.), xvi. (1884) 5 pp.
+ Jenaisch. Zeitschr. f. Naturwiss., xvii. (1884) pp. 941-50.
3 BQ
716 SUMMARY OF CURRENT RESEARCHES RELATING TO
about ; such nuclei are always small and vary in character. Schenk
has already noted the presence of non-nucleated cells in the ectoderm
when describing the process of fusion of the folds of the amnion.
Scales, Feathers, and Hairs.*—The idea largely taught to
students that scales, feathers, and hairs are identical in nature is
combatted by J. H. Jeffries. He considers the epiderm to be the
primitive skin, if not the true one, as it is formed long before the
corium, which is a late and very variable product of the mesoblast ;
and because all the organs of sense are formed from it. The epiderm
may be regarded as primitively consisting of a smooth mucous layer,
an epitrichial layer, and perhaps an intermediate layer of parenchy-
matous cells. In birds and mammals the outer layer is lost, and
never renewed, while the middle layer becomes thickened and subject
to various modifications, as drying, conversion into horn, &c., and
enters into the structure of all the appendages. Scales are moulted
and renewed, scuta are not. The toe-pads of birds may be seen to
pass over into scuta on the sides of the toes of many birds. Scuta
bear feathers as epidermal appendages—scales never do, thus pointing
to scuta, which have a mucous layer and outer horn coat with a
mesodermal core, as simple folds of the skin, not as appendages.
The early stages of a feather and of a hair differ. The latter is
formed in a solid ingrowth of the epiderm, the latter from the
epiderm of a large papilla. A hair does not contain any of the
mucous cells, while a considerable portion of a feather consists of
them. The supposed homology between feathers and scales seems to
fail before the facts that the mucous layer is absent in the latter, and
that Studer has shown that the imagined scale-like nature of the
remiges of penguins is a fallacy. Mr. Jeffries avows his belief in the
distinct origin of the dermal appendages of the higher vertebrates,
and asserts that the nakedness of the Amphibia is a strong argument
against the identity of any of the avian appendages with those of
reptiles and mammals.
Locomotion of Animals over smooth Vertical Surfaces.j—Dr.
H. Dewitz has extended his observations on this subject, at first
confined to insects,t to a variety of other forms, including some
Vertebrata. He finds that the same means, the exudation of a secre-
tion, are adopted in many cases, even where sucking-disks are used.
Thus the leech can walk on a wire network, on which the disks could
not act by exhaustion of the air, and the secretion of the disks of
Piscicola has been examined by Leydig. A long series of animals is
enumerated from Worms and Hchinoderms to Apes among the
Mammalia, which are known with more or less certainty to use similar
means for climbing.
The tree-frog (Hyla) maintains its hold as firmly within the
exhausted receiver of an air-pump as in the open air, and in fact a
piece of glass passed over the balls of the tips of the toes shows clear
* Proc. Bost. Soc. Nat. Hist. Cf. Amer. Natural., xviii. 1884) p. 640.
+ Pfliiger’s Arch. gesammt. Physiol., xxxiii. (1884) pp. 440-81 (3 pls.), See
also infra, Insecta.
t See this Journal, iii, (1883) p. 363.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 717
traces of the secretion. If studied by sections, the ball of the foot
exhibits on the upper surface some globular mucous glands imbedded
in the cutis, and some elongated glands, imbedded in the connective
tissue, on the lower side; this is the case on the balls of all the
phalanges. In Rana temporaria, too, these dermal glands have a
similar form, only being less numerous and long; they probably serve
a similar function.
The glands in Hyla are tubular, there is a tunica propria, and the
cells are longish and somewhat cubical in longitudinal, but mostly
hexagonal in transverse section; the nucleus, which is the only part
which is stained readily by picrocarmine, lies at the lower end; the
cells end distally in two pointed processes. The glands do not open
in the annular furrow, but over the whole of the sole, especially at the
hinder part; the ducts are lined by a cuticle which is shed with the
skin. The spongy connective tissue of the ball of the toe is filled
with lymph, and is thus rendered elastic, so that it adapts itself to
inequalities of surface; balls of similar structure are found on the
tarsal joints of Orthoptera. By fastening insects feet upper-
most on the under side of a covering-glass which projects from a
glass slide, the hairs which clothe the grasping lobes of the foot may
be seen (e. g. in Musca erythrocephala) to be tipped with drops of trans-
parent liquid. On the leg being drawn back from the glass, a
transparent thread is drawn out, and drops are found to be left on the
glass.
The grasping apparatus is constructed as follows : The short grasp-
ing foot-hairs in Telephorus and other Coleoptera are each traversed
by a canal which opens at its extremity. Sundry long hairs on the
lower side of the tarsal joints in Telephorus are connected with nervous
filaments which lead from small ganglia, and thus constitute tactile
organs. The observation of what appear to be nerve-fibres in the
glands which supply the hairs with the sticky secretions is not suffi-
ciently certain.
In the Orthoptera the arrangement is different: thus the tarsus of
a Locustid has the chitinous covering of the lower side rendered
very flexible by being composed of small parallel tubes, the under-
lying matrix is deeply plicate, and constitutes a large gland, whose
secretion is transmitted through the chitinous tubes and through another
intermediate chitinous layer to the surface. In the house-fly, the
grasping foot-lobes appear to be only called into play when the insect
has to walk on vertical smooth surfaces, for in other cases they hang
loosely down. So also the Echinoidea use the tube-fect only on
vertical surfaces.
The use of a glutinous secretion for walking has been shown by
Burmeister for Dipterous larve; Dr. Dewitz finds the larva of a
Musca to use for the purpose a liquid ejected from the mouth. Thus,
too, the larve of Leucopis puncticornis accomplish their loop-like
walk—the liquid in this case comes from both mouth and anus. A
Cecidomyia-larva is able to leap by fixing its anterior end by means
of a liquid of this kind, The larva of the alder-leaf beetle (Galeruca)
moves by drawing up its hinder end, fixing it thus, and carrying the
718 SUMMARY OF CURRENT RESEARCHES RELATING TO
anterior part of the body forward with its feet until fully extended,
when it breaks the glutinous adhesion; under even the lower powers
of the Microscope the drops of secretion may be seen on the feet.
A Chrysopa-larva (probably Hemerobius) was able to crawl well on
vertical glass, but on sand the feet became clogged ; some larve of this
group, on the other hand, had the grasping lobes but slightly
developed, and these adopted the loop mode of walking; the
adhesion of the posterior end of the body was so strong that many
larve long resisted all attempts to shake them off by twisting the
glass suddenly round.
Among the Hymenoptera the ventral feet of some sawflies have
this power. Most spiders are devoid of it, but leaping spiders leap
and crawl on vertical surfaces, and have grasping disks for adhesion.
Among Celenterata, Hydra may be seen to excrete mucous adhesive
matter from its foot.
Zoology of the Voyage of the ‘ Alert.’*—The Zoological collec-
tions made by Dr. R. W. Coppinger, Staff-Surgeon H.M.S. ‘ Alert’
in the Melanesian Seas and in the Western Indian Ocean were so
large that the Trustees of the British Museum ordered the account
of them to be published as a separate volume. The magnitude of
the collection may be inferred from the statement that “irrespective
of a number of specimens set aside as duplicates not less than 3700
referable to 1300 species were incorporated in the National Collec-
tion ;” of these the most important were marine invertebrates, and
490 of the species are either new or are additions to the Museum.
The specimens were admirably preserved, and collected, Dr. Giinther
says, with singular judgment.
In place of the one species of lancelet which Dr. Ginther thought
to be cosmopolitan, six distinct species are, he now thinks, to be
recognized.
The Mollusca are treated of by Mr. Edgar A. Smith, who finds that
of the Melanesian specimens the general character is Malayan.
The Echinodermata are dealt with by Prof. F. Jeffrey Bell, who
found that 30 of the 124 Melanesian species were new; fifteen of
these were Comatulids. He adduces evidence to show that pattern
of coloration is not as important a characteristic of the species of
Ophiothriz as has been generally supposed. He proposes some altera-
tions in the mode of formulating the characters of Crinoids. Having
had the opportunity of examining a large collection from the Sydney
Museum he finds that no view can be more erronecus than one which
speaks of an Australian (marine) fauna without some sort of qualifica-
tion; Cape York and Port Molle are as much part of Australia
as Port Jackson, but between the two faune the resemblance is as
slight as is in the nature of things possible. He concludes, in fact,
that “to-day, as in those Tertiary times when a wider sea separated
the Australian from the Asiatic continent, there are forms whose
breadth of range is coincident rather with isothermal lines than with
topographical boundaries.” The marked manner in which the species
* “Report on the Zoological Collections made in the Indo-Pacific Ocean during
the voyage of H.M.S. Alert, 1881-2.’ 8yvo, London, 1884, 684 pp. (54 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 719
of Crinoids vary among themselves leads to the hope that the details
of the tropical fauna may be elucidated by their aid.
Similarly, according to Mr. Miers, the Crustacea collected have
one-third of their species widely distributed through the Indo-Pacific
region ; the affinity of the Australian with the European Amphipoda
is very remarkable, some of the species being identical. Mr. Miers
gives a very elaborate table of the distribution of the higher
Crustacea on the East Coast of Africa and the adjacent islands.
Mr. 8. O. Ridley deals with the Alcyonaria and Spongiide; of
the former there are 38 Melanesian species, and the author thinks
that few novelties are in the future to be expected from the shallow
water; one-third of the Alcyonaria are new to science; Psilacabaria
is a new genus of Melitheids, and its species is remarkable for the
large size of its spicules. Thirty-eight per cent. of the Melanesian
sponges are certainly new to science; the greater number of novelties
belong to the Ceratosa; as to individual variation, it is noted that
this often affects the size of the spicules; variation in form of the
spicules is less common, that of external form is sometimes very
striking. Only a quarter of the species of sponges are known to
occur outside the Australian seas; the most widely ranging are the
most generalized, but in some cases it is possible that the same specific
characters have been independently acquired. Twenty-eight per cent.
of the sponges obtained in the Western Indian Ocean were found to
be identical with those of the Australian Seas. The most striking
point with regard to the sponges appears to be “the comparative
scarcity of forms showing marked distinctive characters of generic
importance which are not also found in the more familiar Atlantic
fauna.”
B. INVERTEBRATA.
Origin of Fresh-water Faune.*—Prof. W. J. Sollas points out
that the poverty of fresh-water faunz, as compared with marine, is
commonly attributed to a supposed inadaptability on the part of
marine organisms to existence in fresh water. That this is erroneous
is shown by the existence of fresh-water jelly-fish such as Limnocodium,
and still more directly by the experiments of Beudant, who succeeded
in accustoming several kinds of marine mollusca to a fresh-water
habitat. The view of Von Martens that the severity of a fresh-water
climate is prohibitive of the existence of most marine forms in rivers
is insufficient, and a more thorough-going explanation is necessary.
This is to be found in a study of the means by which the distribution
of marine animals is secured.
In the case of stationary forms, free-swimming embryos are distri-
buted over wide areas by currents, and they can never pass from the sea
into rivers, in which the current is always directed seawards. Nor,
probably, could an attached form once introduced into a river perma-
nently establish itself so long as its propagation took place exclusively
through free-swimming larve, for these would be gradually borne
* Nature, xxx. (1884) p. 163.
720 SUMMARY OF CURRENT RESEARCHES RELATING TO
out to sea. Hence, fresh-water animals should not, as a rule, pass
through a free larval stage of existence, nor, as a matter of fact, do
they. In Hydra, fresh-water sponges, and Polyzoa, the young usually
emerge from a horny cyst in the complete state. In the Unionide,
the glochidium-stage provides for distribution without involving a
seaward journey. The young of fresh-water molluscs do not enter
upon a free existence till they are similar to their parents, and
Paludina is viviparous. The suppression of a free-swimming larval
stage not only occurs in fresh-water, but in many marine invertebrates.
This is connected with the fact that the larval stage is in a position
of disadvantage as compared with the adult. Hence there is an
advantage to the organism if the larval stage can be passed over in a
state of seclusion. From this various other modifications follow ;
development in seclusion involves a supply of accessible food, hence
the appearance of yolk and other kinds of nourishment furnished by
the parent to the imprisoned embryo. Again, the secluded larva
being spared the drudgery of working for its own existence, and
supplied with nutriment in a form that puts the least tax on its
digestive powers, a larger balance of energy remains available for
metamorphic changes. Thus arise the phenomena of accelerated and
abbreviated development. Further, the shortening of the larval life
probably leads to the lengthening of the adult life, and shifts the
chances of variation and selection forward into the adult stage. Thus,
animals which hatch out in a complete state will most probably suffer
modifications of that, and not of previous ones, except very indirectly.
Here we discover a direct tendency towards a mode of development
which explains the “arborescent” character of our zoological ciassifi-
cations, i.e. the tendency of the tree of life is now to produce leaves
rather than new branches. In the case of fresh-water faune very
direct reasons have existed for the suppression of the free larval
stage. In this connection may be noticed the richness in species and
the poverty in genera of the fresh-water mollusca.
In discussing the origin of fresh-water faune there are three
hypotheses from which we have to select: (1) that marine forms have
migrated into rivers; (2) that they have migrated into marshes, and
thence into rivers; and (3) that marine areas have been converted
into fresh-water ones. The last course has been the most usual,
especially in the case of non-locomotive forms. Hence the origin of
fresh-water invertebrates is connected with the great movements
which have affected the earth’s crust.
Pelagic Fauna of Fresh-water Lakes.*—O. E. Imhoff first deals
with the “ Langensee,” and refers to the remarks of Crisp as to the
synonymy of some of his species with those previously described by
Gosse, pointing out certain errors or lacune in Gosse’s descriptions.
Dealing with the pelagic fauna of four of the lakes of northern Italy
he adds to them one Flagellate, Dinobryon divergens Imhoff, a species —
of Ceratium, Conochilus volvox, Anurceea cochlearis and longispina,
Asplanchna helvetica, and a species of Polyarthra. Among the
* Zool, Anzeig., vii. (1884) pp. 321-7.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. EAL
Cladocera we have Bythotrephes longimanus of Leydig and a species
of Daphnia.
The pelagic fauna of fresh-water lakes consists of genera which,
like Piscicola or Argulus, are occasionally found there, and others
which do not voluntarily leave it; the latter are divisible into such
as live on true pelagic animals or plants, like Acineta, Vorticella, and
ELpistylis, and others which are truly pelagic (Hupelagici Pavesi), such
as the genera referred to above and Bosmina and Leptodora.
Lowest and Smallest Forms of Life as revealed by the modern
Microscope.*—The following are some of the principal passages of
the lecture delivered by the Rev. Dr. W. H. Dallinger, at the
Montreal meeting of the British Association. The ‘Times’ says ¢
of it, “But, perbaps, the most popular and most generally
instructive feature in connection with biology at Montreal was the
address of Dr. Dallinger, in which he exhibited by word and picture
the wonderful revelations of the lowest forms of life made by the
modern Microscope ; and in which he showed that however easy it
may seem to be to generate life in the proper conditions, no one has
ever yet succeeded in producing ‘ spontaneous generation.’ And here
Dr. Dallinger is in accord with the most competent scientific
opinion.”
Dr. Dallinger said :—‘ The labour, enthusiasm, and perseverance
of thirty years, stimulated by the insight of a rare and master mind,
and aided by lenses of steadily advancing perfection, has enabled the
student of life-forms not simply to become possessed of an incon-
ceivably broader, deeper, and truer knowledge of the great world
of visible life, of which he himself is a factor, but also to open
up and penetrate into a world of minute living things so ulti-
mately little that we cannot adequately conceive them, which are,
nevertheless perfect in their adaptations and wonderful in their
histories. These organisms, while they are the least, are also the
lowliest in nature, and are totally devoid of what is known as organic
structure, even when scrutinized with our most powerful and perfect
lenses. Now, these organisms lie on the very verge and margin of
the vast area of what we know as living. They possess the essential
properties of life, but in their most initial state. And their number-
less billions, springing every moment into existence wherever putre-
scence appeared, led to the question, How do they originate ?—do
they spring up de novo from the highest point on the area of not-life
which they touch? Are they, in short, the direct product of some
yet uncorrelated force in nature, changing the dead, the unorganized,
the not-living into definite forms of life ?
Now this is a profound question, and that it is a difficult one there
can be no doubt. But that it is a question for our laboratories is
certain. And after careful and prolonged experiment and research,
the legitimate question to be asked is: Do we find that in our
laboratories and in the obscured processes of nature now that the not-
living can be, without the intervention of living things, changed into
that which lives? To that question the vast majority of practical
* ‘Times,’ 2nd September, 1884. + Ibid., 4th September, 1884,
722 SUMMARY OF CURRENT RESEARCHES RELATING TO
“biologists answer without hesitancy, ‘No, we have no facts to justify
such a conclusion. Professor Huxley shall represent them. He
says: ‘The properties of living matter distinguish it absolutely
from all other kinds of things;’ and, he continues, ‘the present state
of our knowledge furnishes us with no link between the living and
the not-living.’ Now let us carefully remember that the great doc-
trine of Charles Darwin has furnished biology with a magnificent
generalization—one, indeed, which stands upon so broad a basis that
great masses of detail and many needful interlocking facts are of
necessity relegated to the quiet workers of the present and the earnest
labourers of the years to come. But it is a doctrine which cannot be
shaken. The constant and universal action of variation, the struggle
for existence, and the ‘ survival of the fittest,’ few who are competent
to grasp will have the temerity to doubt. And to many, that which
lies within it as a doctrine and forms the fibre of its fabric, is the
existence of a continuity, an unbroken stream of unity running from
the base to the apex of the entire organic series. The plant and the
animal, the lowliest organized and the most complex, the minutest
and the largest, are related to each other so as to constitute one
majestic organic whole. Now, to this splendid continuity practical .
biology presents no adverse fact. All our most recent and most
accurate knowledge confirms it.
But the question is—Does this continuity terminate now in the
living series, and is there then a break—a sharp, clear discontinuity,
and beyond, another realm immeasurably less endowed, known as the
realm of Not-life? Or, does what has been taken for the clear-cut
boundary of the vital area, when more deeply searched, reveal the
presence of a force at present unknown, which changes not-living into
the living, and thus makes all nature an unbroken sequence and a
continuous whole? That this is a great question, a question involy-
ing large issues, will be seen by all who have familiarized themselves
with the thought and fact of our times. But we must treat it purely
asa question of science; it is not a question of how life first appeared
upon the earth, it is only a question of whether there is any natural
force now at work building not-living matter into living forms. Nor
have we to determine whether or not, in the indefinite past, the not-
vital elements on the earth, at some point of their highest activity,
were endowed with or became possessed of the properties of life. On
that subject there is no doubt. The elements that compose proto-
plasm—the physical basis of all living things—are the familiar
elements of the world without life. The mystery of life is not in the
elements that compose the vital stuff. We know them all; we know
their properties. The mystery consists solely in how these elements
can be so combined as to acquire the transcendent properties of life.
Moreover, to the investigator it is not a question of by what means
matter dead—without the shimmer of a vital quality—became either
slowly or suddenly possessed of the properties of life. Hnough
for us to know that whatever the power that wrought the change,
that power was competent, as the issue proves. But that which
calm and patient research has to determine is, whether matter
ZOOLOGY AND BOTANY, MICROSOOPY, ETC. (pea
demonstrably not living can be, without the aid of organisms already
living, endowed with the properties of life.
Judged of hastily and apart from the facts, it may appear to some
minds that an origin of life from not-life, by sheer physical law,
would be a great philosophical gain, an indefinitely strong support
of the doctrine of evolution. If this were so, and indeed so far as it
is believed to be so, it would speak and does speak volumes in favour
of the spirit of science pervading our age. For although the vast
majority of biologists in Europe and America accept the doctrine of
evolution, they are almost unanimous in their refusal to accept, as in
any sense competent, the reputed evidence of ‘spontaneous genera-
tion’ : which demonstrates at least, that what is sought by our leaders
in science is not the mere support of hypotheses, cherished though
they may be, but the truth, the uncoloured truth, from nature. But
it must be remembered that the present existence of what has been
called ‘spontaneous generation,’ the origin of life de novo to-day by
physical law, is by no means required by the doctrine of evolution.
Prof. Huxley, for example, says, ‘If all living beings have been
evolved from pre-existing forms of life, it is enough that a single par-
ticle of protoplasm should once have appeared upon the globe, as the
result of no matter what agency; any further independent formation
of protoplasm would be sheer waste. And why? we may ask.
Because one of the most marvellous and unique properties of proto-
plasm, and the living forms built out of it, is the power to multiply
indefinitely and for ever !
What need, then, of spontaneous generation? A locomotive on
a great journey, that is specifically endowed with the power to
generate its own steam, surely does not need stationary engines placed
all along the line to generate steam for it. It is certainly true that
evidence has been adduced purporting to support, if not establish,
the origin in dead matter of the least and lowest forms of life. But
it evinces no prejudice to say that it is inefficient. For a moment
study the facts. ‘The organisms which were used to test the point at
issue were those known as septic. The vast majority of these are
inexpressibly minute. The smallest of them, indeed, is so small that
50 millions of them, if laid in order, would only fill the one-hun-
dredth part of a cubic inch. Many are relatively larger, but all are
supremely minute. Now, these organisms are universally present
in enormous numbers, and ever rapidly increasing—in all moist
putrefaction over the surface of the globe.” Referring to an experiment
made with a few shreds of fish muscle and brain in pure water, and
which in a brief space gave rise to a multitude of many living and
moving organisms, Dr. Dallinger asked, “ How did these organisms
arise? The water was pure; they were not discoverable in the
fresh muscle of fish. Yet in a dozen hours the vessel of water is
peopled with hosts of individual forms which no mathematics could
number! How did they arise—from universally diffused eggs, or
from the direct physical change of dead matter into living forms ?
Twelve years ago the life-histories of these forms were unknown.
We did not know biologically how they developed. And yet with
724 SUMMARY OF CURRENT RESEARCHES RELATING TO
this great deficiency it was considered by some that their mode
of origin could be determined by heat experiments on the adult
forms. Roughly the method was this. It was assumed that nothing
vital could resist the boiling point of water. Fluids containing
full-grown organisms in enormous multitudes, chiefly bacteria, were
placed in flasks, and boiled for from 5 to 10 minutes. While they
were boiling the necks of the flasks were hermetically closed, and the
flask was allowed to remain unopened for various periods. The
reasoning was: Boiling has killed all forms of vitality in the flask.
By the hermetical sealing nothing living can gain subsequent access
to the fluid; therefore, if living organisms do appear when the flask
is opened, they must have arisen in the dead matter de novo by
spontaneous generation. But if they do never so arise the probability
is that they originate in spores or eggs. Now it must be observed
concerning this method of inquiry that it could never be final ; it is
incompetent by deficiency. Its results could never be exhaustive
until the life-histories of the organisms involved were known. And
further, although it is a legitimate method of research for partial
results, and was of necessity employed, yet it requires precise and
accurate manipulation. A thousand possible errors surround it. It
can only yield scientific results in the hands of a master in physical
experiment. And we find that when it has secured the requisite skill,
as in the hands of Prof. Tyndall for example, the result has been
the irresistible deduction that living things have never been seen to
originate in not-living matter. Then the ground is cleared for the
strictly biological inquiry, How do they originate ?
To answer that question we must study the life-histories of the
minutest forms with the same continuity and thoroughness with which
we study the development of a crayfish or a butterfly. The difficulty
in the way of this is the extreme minuteness of the organisms.
We require powerful and perfect lenses for the work. Happily
during the last fifteen years the improvement in the construction of the
most powerful lenses has been great indeed. Prior to this time there
were English lenses that amplified enormously. But an enlargement
of the image of an object avails nothing if there be no concurrent
disclosure of detail. Little is gained by expanding the image of an
object from the ten-thousandth of an inch to an inch, if there be not
an equivalent revelation of hidden details. It is in this revealing
quality, which I shall call magnification as distinct from amplification,
that our recent lenses so brilliantly excel. It is not easy to convey
to those unfamiliar with objects of extreme minuteness a correct idea
of what this power is. But at the risk of extreme simplicity, and to
make the higher reaches of my subject intelligible to all, I would
fain make this plain.” Dr. Dallinger then went on to give a series of
greatly magnified illustrations, beginning with the sting of the bee,
and going on through a long series of interesting specimens of the
lowest forms of life. He described and illustrated with great
minuteness experiments in the generation of these forms of life,
from all of which he maintained it to be clearly proved that dead
matter cannot be developed into living.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 725
“ We conclude,” he said, “ with a definite issue—viz. by experiment
it is established that living forms do not now arise in dead matter.
And by study of the forms themselves it is proved that, like all the
more complex forms above them, they arise in parental products.
The law is as ever, only the living can give rise to the living.”
Intelligence in the Lowest Animals.*—“ No one,” writes Dr. G.
J. Romanes, “ can have watched the movements of certain Infusoria
without feeling it difficult to believe that these little animals are not
actuated by some amount of intelligence. Even if the manner in
which they avoid collisions be attributed entirely to repulsions set up
in the currents which by their movements they create, any such
mechanical explanation certainly cannot apply to the small creatures
seeking one another for the purposes of prey, reproduction, or as it
sometimes seems, of mere sport. There is.a common and well-known
rotifer whose body is of a cup shape provided with a very active tail,
which is armed at its extremity with strong forceps. I have seen a
small specimen of this rotifer seize a much larger one with its forceps
and attach itself by this means to the side of the cup. The large
rotifer at once became very active, and swinging about with its burden
until it came to a piece of weed, it took firm hold of the weed with its
own forceps, and began the most extraordinary series of movements,
which were obviously directed towards ridding itself of its encum-
brance. It dashed from side to side in all directions with a vigour
and suddenness which were highly astonishing, so that it seemed as if
the animalcule would either break its forceps or wrench its tail from
its body. No movements could possibly be better suited to jerk off
the offending object, for the energy with which the jerks were given,
now in one direction and now in another, were, as I have said, most
surprising. But not less surprising was the tenacity with which the
smaller rotifer retained its hold. ... This trial of strength, which
must have involved an immense expenditure of energy in proportion
to the size of the animals, lasted for several minutes, till eventually
the small rotifer was thrown violently away. It then returned to the
conflict, but did not succeed a second time in establishing its hold.
The entire scene was as like intelligent action on the part of both
animals as could well be imagined, so that if we were to depend
upon appearances alone, this one observation would be sufficient to
induce me to attribute conscious determination to these microscopical
organisms.
But without denying that conscious determination may have been
present, or involving ourselves in the impossible task of proving such
a negative, we may properly affirm that until an animalcule shows
itself to be teachable by individual experience we have no sufficient
evidence derived or derivable from any number of such apparently
intelligent movements that conscious determination is present.
Therefore I need not wait to quote the observations of the sundry
microscopists who detail facts more or less similar to the above, with
expressions of their belief that microscopical organisms display a
* ‘ Animal Intelligence,’ 8vo, London, 1882.
726 SUMMARY OF CURRENT RESEARCHES RELATING TO
certain degree of instinct or intelligence as distinguished from
mechanical or wholly non-mental adjustment. But there are some ob-
servations relating to the lowest of all animals, and made by a com-
petent person which . .. in my opinion prove that the beginnings
of instinct are to be found so low down in the scale as the Rhizo-
poda.”
The observations of Mr. H. J. Carter are then quoted.* One
relates to Afthalium, which will make its way over the side of a watch-
glass to get to the sawdust in which it has been living. In another
case he saw an Amcba climb up the stalk of an Acineta which con-
tained a young one (“tender and without poisonous tentacles”), place
itself round the ovarian aperture, receive the young one, incept it,
descend from the parent, and creep off with it. This Dr. Romanes
considers, although certainly very suggestive of something more than
mechanical response to stimulation, is not sufficiently so to justify us
in ascribing to these lowest members of the zoological scale any rudi-
ment of truly mental action. The subject, however, is here full of
difficulty, and not the least so on account of the Amebe not only
having no nervous system, but no observable organs of any kind, so
that, although we may suppose that the adaptive movements described,
by Mr. Carter were non-mental, it still remains wonderful that these
movements should be exhibited by such apparently unorganized
creatures, seeing that as to the remoteness of the end attained, no less
than the complex refinement of the stimulus to which their adaptive
response was due, the movements in question rival the most elaborate
of non-mental adjustments elsewhere performed by the most highly
organized of nervous systems.
In Ceelenterates Dr. Romanes notices M‘Crady’s account of a
medusa which carries its larve on the inner side of its bell, moving
the manubrium from side to side to give suck to the larve on the
sides, but he does not consider this is due to intelligence. The mode
in which Sarsia seeks the light is in the nature of a reflex action, and
he does not concur in Dr. Himer’s distinction between the “involun-
tary ” and “ voluntary ” movements of medusze.
Some of the natural movements of the Echinodermata, as also
some under stimulation, are very suggestive of purpose, but Dr.
Romanes has satisfied himself that there is no adequate evidence of
the animals being able to profit by individual experience, so that there
is no adequate evidence of their exhibiting truly natural phenomena.
Of Vermes, the only instances cited are Mr. Darwin’s observations
on earth-worms, and Sir E. Tennent’s on Ceylon land-leeches.
In Mollusca, the more important observations relate to snails,
limpets, and oysters. There is no doubt, he considers, that if a larger
sphere of opportunity permitted, adequate observation of the Cepha-
lopoda would prove them to be much the most intelligent members of
the Sub-kingdom.
The foregoing occupies pp. 18-30 of Dr. Romanes’s book ; the
remainder (pp. 31-498) deals with Ants, Bees and Wasps, Spiders and
Scorpions, remaining Articulata and the Vertebrates.
* Ann. and Mag. Nat. Hist., xii. (1863) pp. 45-6.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 127
Mollusca.
New Type of Mollusc.*—W. H. Dall describes a remarkable new
form of mollusc, being a pelecypod or lamellibranch with an internal
shell.
The animal is about 1 in. in length, somewhat of the shape of a
small globose Cyprea, of inflated ovoid form, translucent, jelly-like,
dotted above with small, rounded papille, which appear of an opaque
white on the general translucent ground. The mantle which covers
the dome of the body is tough and thick: the sides are smooth, and
nearly free from papille. The superior median line is a little
depressed. The basal part of the anterior end in life is prolonged
beyond the general mass in a wide trough, with the convexity up-
ward, and somewhat expanded at its anterior extremity. About one-
third of the way from the anterior end, the mantle is perforated by
an orifice, which pierces it in the vicinity of the mouth. The edges
of this orifice project from the general surface, and it is lined with
close-set, small papilla. At about the same distance from the
posterior end is another tubular perforation, holding a similar rela-
tion to the anus; which has, however, plain edges, and is not in-
ternally papillose.
Turning the animal over, we find the anterior trough of the
mantle prolonged backward, like a slit with plain edges, to about the
posterior third; from this projects a narrow, hatchet-shaped foot,
with a strongly marked byssus-gland at its posterior angle; from this
a bunch of white byssus extends to the stone or other object to which
the mollusc attaches itself. The cavity of the mantle extends some
distance behind the commissure of the pedal opening. The anterior
point of the foot is roofed by the trough-like expansion above men-
tioned. The mouth is provided with two pairs of small palpi. Two
gills, very finely microscopically laminate, extend backward from
near the mouth, on each side, to the posterior end of the body, the
wider one being the inner: between their posterior ends a thin
reticularly perforate veil connects the two pairs, and shuts off the
anal area from the rest of the mantle cavity. The intestine contains
a hyaline stylet, and is considerably convoluted ; but the viscera offer
no marked peculiarities when compared with ordinary pelecypods.
The shells are enclosed in two little sacs in the substance of the
mantle. The umbones are near together, apparently connected by a
brown gristle resembling an abortive ligament, and are nearly over
the heart. The valves are about 10 mm. long and 1 mm. wide,
destitute of epidermis, prismatic or pearly layers. There are no
muscular or pallial impressions, no adductors, hinge, or teeth. The
resemble in form the exterior of Gervillia, as figured by Woodward,
and are pure white. As they lie in the body, they diverge at a rather
wide angle from the beaks, forward. The embryonic valves are
retained like two tiny bubbles on the umbones.
Whatever be its relations to the higher groups, a point to be
determined by further study, there can be no doubt that the animal
* Science, iv. (1884) pp. 50-1.
728 SUMMARY OF CURRENT RESEARCHES RELATING TO
forms the type of a new family, Chlamydoconcha, and the author
gives it the name of Chlamydoconcha Orcutti. It is evident already,
that the genus does nothing toward bridging the gap between the gas-
tropods and pelecypods, but is simply a remarkably aberrant form
of the latter group, and probably derived from some form with an
external shell.
Taking-in of Water in relation to the Vascular System of
Molluses.*—E. Ray Lankester, while recognizing that the supposi-
tion that water is admitted by pores into the vascular system of
molluses is supported by the commonly received doctrine that water
is admitted by the madreporite to mix with the ccelomic fluid of
Echinoderms, and that its correlated outpouring is favoured by the
undoubted fact that the ccelomic fluid is occasionally shed through
the dermal pores of the earthworm, doubts its occurrence in molluscs
in consequence of having ascertained the presence of hemoglobin in
the plasma of the blood-fluid of Planorbis, and in the corpuscles of
Solen legumen. In Solen no shedding-out of blood-fluid occurs while
the surface of the animal is uninjured, and the complete distension of
the foot is produced by the simple mechanism of a rapid flow of
blood from the mantle and body into the foot. Planorbis presents.
evidence of essentially the same kind.
A distinction must be made between the outpouring of the
vascular fluid and the introduction of water through pores on the
surface ; on the whole there seems to be no sufficient proof that the
pericardium of molluscs is in any case (except that of the
Neomeniz) a blood-space; and, therefore, the blood cannot escape
through it and the renal organs to the exterior.
The view that water is introduced by pores in the foot is not
supported by Lankester’s observations on Anodon or Solen, and these
pores must be demonstrated, by the supporters of the doctrine, in a
way which will satisfy a histologist, and the evidence must not be
allowed to rest on experiments made by the diffusion of a soluble
colouring matter; it is to be noted that Griesbach, the present leading
supporter of the doctrine, has found that finely divided coloured
powder cannot be made to enter the vascular system through the
surface of the foot.
Eyes and other Sense-Organs in the Shells of Chitonide.t—
H. N. Moseley, on examining a specimen of Schizochiton incisus
dredged in the Sulu Sea, was “astonished to remark on the shells
certain minute, highly refracting, rounded bodies arranged in rows
symmetrically.” On further examination they were found to be eyes,
and on search being made in other genera, they were detected in the
majority, but in each genus they differ more or less in structure and
arrangement. These eyes are entirely restricted to the outer surface
of the shells on their exposed areas, and do not extend on to the
lamine of insertion; they are mostly circular in outline, and measure
from 1/175 to 1/600 in. They are surrounded and set off by a
narrow zone of dark pigment, and in the centre of each convex spot
* Zool. Anzeig., vii. (1884) pp. 343-6.
+ Ann. and Mag. Nat, Hist., xii, (1884) pp. 141-7.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 729
is a smaller darker area, due to the outline of the iris, but with a
brilliant speck of totally reflected light, due to the lens. Numerous
longitudinal canals lodge a specially large stem of soft tissue and
nerves, which ramifies towards the surface and terminates either in
eyes or in peculiar elongated bodies which are, apparently, organs of
touch. From these latter the eyes may be supposed to have arisen by
modification. The cornes, which are calcareous, are seen in section
to be formed of a series of concentric lamelle ; the pear-shaped cavity
of the eye is lined by a dark brown pigmented choroid of a stiff and
apparently somewhat chitinous texture, The lens is perfectly trans-
parent and strongly biconvex. At some distance from the eye the
optic nerve is a compact strand, but in the very long tube continuous
with the choroid its numerous fine fibres are much separated from one
another. The retina is formed on the type of that of Helix; and not
as might be supposed, on that of the dorsal eyes of Oncidium ; it is not
perforated by the optic nerve, but it is composed of a single layer of
very short, but extremely distinct and well-defined rods, with their
ends directed towards the light. A number of the fibres of the nerve
do not enter the retina at all, but terminate in small plugs of tissue
corresponding to the minor organs of touch; they appear to form a
sensitive zone round each eye. The choroid sacs have a curious open
fold which calls to mind the choroid fissure. In some genera—e. g.
Chiton—eyes are entirely absent, though the small and large touch-
organs are present.
The difficult problem of the classification of the Chitonide will
probably be rendered easier, owing to the differences in arrangement
and number of the eyes in different genera; in Corephium aculeatum
there must be 3000 on the anterior shell alone, counting only those
in good condition; and on the remaining shells as many as 8500.
Prof. Moseley has been unable to trace the nerves to their source,
but he doubts not that they proceed from the parietal (branchial)
nerve. He concludes that the tegmentary part of the shell of the
Chitonide is something swi generis, entirely unrepresented in other
Mollusea. Its chief function seems “to be to act asa secure protection
to a most extensive and complicated sensory apparatus, which in the
Chitonide takes the place of the ordinary organs of vision and touch
present in other Odontophora,” There are some curious resemblances
to the Brachiopoda,
The eyes are ordinarily hard to see on a dried shell with a power-
ful lens ; the shell should be wetted with spirit and examined with a
lens as powerful as Hartnack’s No. 4 objective.
Renal Organs of Embryos of Helix-*—P. de Meuron describes
the primitive renal organs of Heljx as arising from ectodermal invagi-
nations, and not as being mesodermal in origin as are, according
to Rabl, the kidneys of the aquatic Pulmonata. The walls of the
organ are formed by large cells, with enormous nuclei, which are set
in a radiate fashion round the central canal of the tube; some of
the cells become of a particularly large ‘size, as in the forms studied
* Comptes Rendus, xcviii. (1884) pp. 693-5.
Ser. 2.—Von. IV. 5.0
730 SUMMARY OF CURRENT RESEARCHES RELATING TO
by the German embryologist. The internal end of the organ is very
difficult of detection among the mesodermal cells by which it is
surrounded; however, there appears to be an orifice which is pro-
vided with vibratile cilia, essentially similar to what has been seen by
Fol in the aquatic Pulmonata, and by Jourdain in slugs.
The primitive kidney does not as in Bithynia (Sarasin) appear to
have any relation to the velum. The permanent renal organ seems
to be formed from an ectodermal invagination, and a mesodermal
growth. The author suggests that the pericardiae cavity is the
cavity of s somite, and that another is indicated by the primitive
kidney which is the excreting organ of the anterior, as is the
permanent kidney of the posterior somite.
Nervous System of Parmophorus australis.*—M. Bontan de-
scribes the nervous system of the Gasteropod Parmophorus australis,
specimens of which were collected near Sydney, as being similar in
its main features to that of _Haliotis,as described by Lacaze-Duthiers.
The line of papille between the foot and the first fold of the mantle,
is the homologue of the festooned border of the collarette of Haliotis.
This row of papille forms part of the mantle, and cannot be referred
to the foot. The study of Parmophora, in which the nervous centres
are more separated than those of Haliotis, leaves no doubt in this
respect.
Organization of Haliotis.;—H. Wegmann considers that Haliotis
has many points in common with the Acephala. Thus :—There is a
coecum between the stomach and the intestine. The digestive tube
is ciliated throughout its greater portion. There are the same con-
nections between the liver and the digestive tubes as in the Lamelli-
brancks.
A series of organs, such as the renal organ, the auricle, and the
gill, are in pairs instead of being odd. Two rudimentary gills, with
the two that are developed, make up the four of the Acephala. The
cardiac ventricle is traversed by the rectum. Two arterial passages
arise from the two extremities of the heart. The venous circulation
is in its fundamental characteristics that of the Acephala, and the
position of the right renal organ between the branchie and the system
is especially important. The structure and relationships of the renal
organs are essentially the same in the two cases. There is also a
remarkable simplicity in the genital apparatus; a complete absence
of accessory glands and copulative organs; and a singular connection
with the right renal organ, as in many of the Acephala.
Absorption of the Shell in Auriculide.{—Crosse and Fischer
illustrate and describe the peculiar absorption of the inner parts of
the upper whorls of the shell in this family, and also in the genus
Olivella. These animals appear to have the power of dissolving
entirely the internal partitions of the shell, from a point some distance
inside the aperture to the very apex. The only exception in the
* Comptes Rendus, xeviii. (1884) pp. 1385-7. { Ibid., pp. 1387-9.
{ Journ. de Conchyl., xxii, (1883) p. 3. Cf. Science, ii. (1883) pp. 663-4.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 731
family Auriculide is the genus Pedipes, in which the partitions were
found intact. The absorption is not always complete, nor are tke
same parts invariably missing. Complete absorption was observed
in Melampus, Auricula, Blauneria, Marinula, Tralia, Alexia, Monica,
Plecotrema ; only partial absorption in Cassidula and Scarabus. The
case of Olivella is more remarkable, since the allied groups Oliva,
Ancillaria, &c., do not, according to the authors, present this
peculiarity at all. Tryon, however, observes * that in Oliva reticularis
he has found the walls absorbed away, so that very little of the sub-
stance remained, and considers it probable that all shells with close
volutions are in the habit of absorbing them internally. It is
certainly the case with many of them.
Development of the Digestive Tube of Limacina.{—S. Jourdain,
having reminded us that the first indication of the pharyngeal
vestibule of the Limacina appears as an invagination of the vitelline
mass, and that, later, another invagination, which corresponds to the
anal opening, appears in the middle line, between the two external
openings of the segmental organs, now tells us that the base of the
pharyngeal invagination is continuous with a cavity, the walls of
which are mesodermal and are lined by endodermal cells. The diges-
tive tube has, at this period, the form of a sac ending in a spherical
diverticulum, which will become the gland that is incorrectly spoken
of as the liver. This gland has at first a mesodermal and an endo-
dermal origin; the framework being formed of mesoderm, and the
secreting tissue of endoderm. The hepatic tissue is filled with a
finely granular fluid, which is coagulated by heat, alcohol, or nitric
acid, but does not lose its tramsparency ; it is a kind of secondary
yolk, the quantity of which increases rapidly during the early periods
of embryonic development, and which fills the digestive tube. It
probably arises from the elaboration of the albumen of the egg and
is digested by the embryo during its development.
The internal wall of the alveoli of the hepatic sac gives rise to
cells by budding; these cells gradually take on the characters of the
secreting elements of the liver, so that each alveolus becomes a lobe
of the hepatic organ. This organ ought not to be called a liver: it
is only a diverticulum of the stomachal portion of the intestinal tract.
It performs so many functions that it would be better spoken of as a
chylific gland. Moreover, its mode of development may explain the
bizarre forms that it sometimes attains, as for example, in the
Eolidiw, where we may suppose that each of the alveoli of the organ
became isolated, acquired a great size, and took the form of the varied
appendages which are found in those Gastropoda,
Molluscoida.
Simple and Compound Ascidians.,—W. A. Herdman is unable
to find a single satisfactory character by which to distinguish simple
from compound Ascidians. Reproduction by gemmation and the
* Man. Conch.: Olivella, p. 64.
+ Comptes Rendus, xeviii. (1884) pp. 1553-6.
~ Nature, xxix. (1884) pp. 429-31.
a oY
732 SUMMARY OF CURRENT RESEARCHES RELATING TO
formation of colonies in the latter group will not hold, since it is
possible to pass from Ciona—a typical simple Ascidian—to Distoma
and the very heart of the compound Ascidians through the following
series of forms, which shows a perfect gradation of these characters :—
Ciona, Rhopalea, Ecteinascidia, Clavelina, Diazona, Chondrostachys,
Oxycorynia, Distoma. The formation of common cloacal cavities,
canals, and apertures cannot be considered as a diagnostic feature of
the compound Ascidians, as there are forms considered by all autho-
rities as Synascidie, such as Chondrostachys, Diazona, Distoma, and
others, in which the atrial apertures of the Ascidiozooids open inde-
pendently on the surface of the colony, and no common cloaca is
formed.
The characters taken from the condition of the test, break down
like the others. In the first place, in passing along the series of
forms connecting Ciona and Distoma, we encounter all stages between
a distinct test or tunic for each individual, and a common mass in
which a number of Ascidiozooids are imbedded. And secondly, the
remarkable group “ Polystyele” presents many of the characters of
highly differentiated simple Ascidians (the Cynthiid) along with the
supposed Synascidian feature of a colony composed of many Ascidio-.
zooids completely buried in a common test.
Digestion in Salpa.*—Dr. C. 8. Dolley combats the view of Korot-
neff as to the existence of a large amceboid cell or plasmodium in the
cesophagus or stomach of Salpa which carries on a form of parenchy-
matous digestion of the food passing the resulting chyle into the
walls of the intestine by means of its pseudopodia.
Dr. Dolley has observed the appearance in the intestines of Salpa,
which had been described by the Russian author, but he suggests an
entirely different interpretation. In Salpa we find a large branchial
sac, representing the true pharynx, at the posterior portion of which
is the stomach. The endostyle, or thickened bottom of a fold or
groove of the branchial sac, throws out a supply of mucus, which
covers the surface like a curtain, and in which nutritive particles
finding their way into the animal are imbedded. The food is carried
back by cilia, and the mucous sheet is wound up into a thread, which
can be traced into the cesophagus, and from there to the stomach.
This mucous exudation is the ameeboid cell of Korotneff.
Fresh-water Bryozoa.t—K. Krapelin has been able to find, in
the neighbourhood of Hamburg, examples of all the genera (except
perhaps Lophopus) of Bryozoa that are known to inhabit the fresh
waters of Europe. In addition to these he found large masses formed
by colonies of Pectinatella magnifica, described by Leidy as living
near Philadelphia. In this genus, in Cristatella, and possibly also
Lophopus, the statoblasts are set free on the death of the colony.
The author asks for the assistance of correspondents for the purpose
of making a more complete investigation into the biology and geo-
graphical distribution of these animals.
* Proc. Acad. Nat. Sci. Philad., 1884, pp. 113-5.
t Zool. Anzeig., vii. (1884) pp. 319-21.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 733
Supposed new species of Cristatella.*—E. Potts describes the
discovery of aggregations of colonies of a species of Cristatella (C.
lacustris) apparently differing from C. mucedo of Europe and C. Ide
and C. ophidioidia of America. He considers it to be at least as
clearly differentiated from any of the other species as they are from
each other, though probably, as the differences existing amongst them
are not considerable, all should be merged under C. mucedo.
Arthropoda.
a. Insecta.
New Type of Elastic Tissue, observed in the Larva of Eris-
talis.| —H. Viallanes has directed his attention to the curious
movements of the respiratory tube which is found at the end of the
body in the larve of Hristalis. It is formed of a number of cylinders,
which can be shortened or elongated at the will of the animal: the
elongation is effected by the contractions of the body, by means of
which fluid is driven into it, and its shortening by special muscles
and internal elastic bands. ach of these elastic bands is formed by
a single cell, which is so constructed as to act as a piece of caout-
chouec. The cell is fusiform in shape, and, while one of its extremities
is attached to the neighbouring integuments, the other is prolonged
into a process which is fixed to the inner face of the respiratory tube.
The cell and its prolongation are invested ina membrane, which is of
some thickness, but is very elastic. At the centre of the cell there is
a very large spherical nucleus, which is surrounded by a quantity of
protoplasm, which is also found in the prolongation. Within the cell
itself there is developed a long elastic fibre, similar in its physical
properties to those seen, for example, in the cervical ligament of a
mammal; it is folded a large number of times around the nucleus,
and passes in a straight line through the prolongation of the cell, to
the extremity of which it is attached; by the other it fuses with the
protoplasm of the cell. When the cell is drawn out the coiled
portion becomes unfolded.
The facts detailed are of interest, as proving the high degree of
complexity that may be attained within the limits of a single cell,
and as throwing a new light on the morphology of elastic tissue,
since they show that this may be, as in vertebrates, developed in the
intercellular substance, or, as in Fristalis, in the protoplasm itself.
It may be noted that striated muscular tissue presents analogous
variations.
It would seem, then, that the same tendency obtains in elastic as
in muscular tissue; in both cases, perfection is attained by parts
leaving the protoplasm of the cells to which they primitively be-
longed, and, by becoming intercellular, being converted into the
undivided property of neighbouring cells.
Submaxillary of the Jaw of Mandibulate Insects.{—J. Chatin
retains the name of submaxillary for the part of the buccal apparatus
* Proc. Acad. Nat. Sci. Philad., 1884, pp. 193-9 (1 pl.).
+ Comptes Rendus, xeviii. (1884) pp. 1552-3.
t Ibid., xcix, (1884) pp. 51-3.
734 SUMMARY OF CURRENT RESEARCHES RELATING TO
so named by Brullé, and called the cardo by Kirby and Spence.
Oligotoma Saundersii is taken as the starting point, and its sub-
maxillary described as being a small transverse piece slightly grooved
on its inner surface. Cdipoda cinerascens has the same part provided
with several deep articular cavities. In Decticus the organ is still
more modified. In Gryllus domesticus it is strongly, and in Phasma
japetus feebly articulated. In Maniis religiosa it is developed in a
vertical direction, and has the appearance of some maxille. In
Hydrophilus piceus the different portions of the organ are profoundly
modified. ‘The author considers that the descriptions which he gives
are sufficient to show the interest which attaches to the morphological
study of the submaxillary, and the changes undergone by a part which
has been too often misunderstood, but whose correct interpretation
is necessary in a comparative study of the appendages of the
Arthropoda.
Structure and Function of Legs of Insects.*—F. Dahl ascribes
our ignorance of the structure and functions of insects’ legs to the
fact that on the one hand most entomological works are of a purely
systematic character, and that, on the other, anatomists have chiefly
busied themselves with the axial parts only; in fact, Strauss- |
Durckheim, Newport, Burmeister, and Graber are the only authors
to whom Dahl makes reference in his introduction.
The constancy of the number of six is probably to be explained
as being in relation to the function of the legs as climbing organs;
‘one leg will almost always be perpendicular to the plane when the
animal is moving up a vertical surface; and on the other hand we
know that three is the smallest number with which stable equilibrium
is possible; an insect must therefore have twice this number, and the
great numerical superiority of the class may be associated with this
mechanical advantage. ‘This theory is not weakened but rather
supported by the fact that the anterior pair of legs is rudimentary
in many butterflies, for these are almost exclusively flying animals.
The author describes in some detail the arrangements of the
muscles of the legs; the nerve-cord supplying them is pretty stout,
and the large number of filaments sent to the joints of the tarsus
lead to the supposition that these have a tactile function ; the nerve-
fibres are seen to enlarge into thick spindle-shaped ganglia. There
are two tracheal trunks.
The prime function of the legs is locomotor, and insects move
through gaseous, fluid, and solid media. The last is seen in fossorial
forms, of which Gryllotalpa may be taken as the type; here some of
the joints are flattened out and provided with teeth, and the muscles
are well developed. In some cases legs of a fossorial type are
possessed by insects which move on the ground, but the larve of
which are subterranean in habitat. The water-beetles and aquatic
Rhynchota have the legs converted into swimming organs; they are
widened out into plates and provided at the sides with movable hairs,
which are directed slightly backwards. The median pair of legs in
Corisa is provided with two very long hooks, the function of which is
* Archiv f. Naturg., 1. (1884) pp. 146-93 (2 pls.)-
ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 735
to fix the animal at some depth among the water-plants, and so to
prevent its floating upwards.
In the aerial forms we have first to notice those that move on the
surface of the water; in these the legs are often provided with con-
siderable enlargements of the tracheal trunk, by means of which they
are enabled to float. Others have very long legs by which they can
balance themselves and extend over a large surface of the water; the
lower surface of the tarsal joints, or that which is in contact with
the water, is provided with thick hairs. In some Diptera hairy lobes
are developed. Arrangements for climbing are very widely dis-
tributed, and are very various in character; the most common are
hooks which by their sharp tips are able to enter the smallest
depressions and so obtain a firm hold; sometimes they are cleft and
are thus adapted to hold on to fine branches; sometimes they are
pectinate and enabled to catch hold of fine hairs.
In very many cases there are organs of fixation; in the locust
they have their chief mass made up of a large number of free flexible
rods (not tubes). The periphery is occupied by scales which corre-
spond in number to the rods, with which they appear to be connected
by fibres; the space between the rods is filled with a fluid. Below
these are groups of spindle-shaped cells which appear to be glandular
in character. The fixing surface of the Hymenoptera, Neuroptera,
and Lepidoptera consists of an unpaired lobule placed between the
hooks ; their structure is most complicated in the first-named order.
Observations on Vespa crabro did not result in the detection of any
space which could be regarded as a vacuum. The lower surface of
the lobule is soft and almost smooth; a few short hairs may be
developed at its base; below this is a hard chitinous mass with
stronger hairs. The upper surface is either covered with hairs or is
finely folded. Near the base is a chitinous plate carrying a pair of
strong sete. Within is an elastic bar which is rolled up in a con-
dition of repose ; when extended it brings the lobule into contact with
the surface on which the insect is standing. ‘There are no well-
developed gland-cells. After descriptions of other modes of fixation
the author gives the following table.
A. Organs of attachment at the end of the foot.
a. Without fixing hairs ee, “sey | 00st a6. aia ge Pe ae ee
Forficula.
8. With fixing hairs ve {Centr
Sialis.
B. Organs of attachment between the hooks.
a. A distinct median lobe.
a. The median lobe with chitinous arches,
1. Secondary in addition to the median lobe Neuroptera.
2. No secondary lobes .. .. . .. .. Hymenoptera.
b. No chitinous arches i Tenover
ipula.
B. No distinct median lobe.
a, Thedobes hairy: -;, (Pai acl Be hae pie,
b. The lobes not hairy .. . «. « #« #Rhynchota,
736 SUMMARY OF CURRENT RESEARCHES RELATING TO
The legs may, further, have a sexual function as attaching or
holding organs; or, as in Mantis religiosa, Nepa cinerea, &c., they
may be of use in seizing prey; and, finally, they may be used as
cleansing organs. The legs in ants may be seen to be pectinate, an
admirable arrangement for forms that live in dust and earth; they are
often specially adapted for cleansing the proboscis, and for other
functions for an account of which we must refer to the paper itself.
Organs of Attachment on the Tarsal Joints of Insects.*—
G. Simmermacher first takes up the case of sexual organs of attach-
ment in the Coleoptera; where the males have some of the tarsal
joints more or less remarkable on account of their widened form, and
for the possession on the lower stirface of stickers which are visible to
the naked eye. The differences between males and females are best
seen in the Dyticid#, where the first three tarsal joints of the first
pair of limbs are distinguished from those that succeed them, on
account of their greater breadth ; those of the second pair are a little
less remarkable. The suckers that are developed belong to the group
of modifications which were associated together by Plateau under the
head of “cupules sessiles,” but the author finds that the large
suckers have a stalk, and they are, further, distinguishable from the
smaller suckers by the presence of better developed and more
numerous ridges. The stalk is traversed by a canal. The disposition
of the suckers on the joints is described:
The tarsi are moved by a strong muscle, the long axis of which is
parallel to that of the foot; it is attached to the chitinous exoskeleton
at every joint, and consists of several muscular fibrils, through which
pass branches of the tracheal system; the muscle is attached to the
stalk of the sucker, the movement of which is, therefore, under the
control of the will. The suckers are to be found on the tarsi of the
males of all the twelve génera of Dyticide living in Germany;
the differences seen are found to be constant in genera and species;
such differences as obtain are due to (a) either the tarsal joints of
the first and second pair of feet are partly widened out and beset with
suckers (Dyticus), or there are suckers on the first pair only (Cybister) ;
(@) the three tarsal joints on the first pair are very greatly widened
and rounded, and those of the second are but little altered (Dyticus),
or, as in Hybius, the first pair of feet are but little altered; (7) the
suckers are either rounded (Dyticus), or elongated as in Cybister ;
(6) the suckers on one and the same joint are either all similar, or they
differ in form or size, or in the form of their joints. A systematic
description of the organs is given for the different genera.
Simmermacher is of opinion that the grooves on the wing-covers
of the female Dyticide have no function in copulation, and in this
he agrees with the results lately obtained by Dr. Sharp, whose im-
portant monograph he did not see till the first part of his own work
had been concluded.
The Carabide and Cicindelide are next dealt with in the same
manner.
* Zeitschr. f. Wiss: Zool., xl. (1884) pp: 481-556 (3 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. rio Yt
In the second part of the essay climbing organs are dealt with;
in the Chrysomelide, Hylobiide, Telephoride, and Cerambycida,
the tarsi, in both sexes, are provided on their lower surface with
chitinous structures which to the naked eye have the same appearance
as those which are found in the males only of the families already
discussed. The groups just mentioned live either in water or on
leaves or stems, where they move about by means of the tubules
covering their tarsi, and by the aid of which they can fix themselves
in various positions. ‘These chitinous structures are always tubular,
and they are never found on more than the first three joints of the
tarsi. In the tetramerous forms they are widened out and have a
distinct orifice, but in the pentamerous Telephoride they end in a
sharp point. In most cases the tubules pour out a secretion, and it is
probable that we have here to do with the phenomena not of actual
attachment by, as it were, glueing, but of adhesion ; the orifice of the
tubes is directed obliquely, and the tubes are, at this point, extremely
delicate and flexible, so as to adhere by their lower surface; in this
adhesion they are aided by the secreted fluid.
In the Cerambycide there is no secretion, and the tubules are
merely sucking organs, analogous to those which are found in the
male Silphide.
Discussing the Diptera, observations on which have been made by
a number of naturalists whose results are here compared, the author
describes the ordinary arrangement (such as is seen, for example, in
the common house-fly) as consisting of two attaching lobes; between
these there is a rod-shaped elongated piece, beset with chitinous
hairs. He does not accept the theory by which the movement of the
fly along smooth surfaces is ascribed to an alternate fixation and
separation, but believes in a process of adhesion, aided by a secretion,
just as in the case of the Coleoptera. The attaching lobes closely
beset with chitinous hairs are enabled, in consequence of the pressure
of the foot, to completely lie along any smooth surface; this expels
the air beneath the lobes, which are then acted on by the pressure of
the outer air.
There are a few observations on the Hemiptera, Neuroptera,
Lepidoptera, Hymenoptera, Orthoptera, and Strepsiptera; and, in
conclusion, analogous cases are cited from other divisions of the
animal kingdom ; sucking tubes are seen in the Acinete, ambulacral
feet in Echinids and Asterids, sucking organs of attachment in Chiton
and Patella, suckers in the Cestoda and the Hirudinea; Schmidt
regards the pectines of the scorpion as having a similar function,
and numerous examples are to be found among Vertebrates.
Locomotion of Insects on Smooth Surfaces.*—Dr. J. E. Rom-
bouts writes as follows :—
“‘T have concluded from my experiments that it is not the pressure
of the air nor the power of an adhesive liquid that gives flies the
faculty of running over smooth bodies, but that the power should be
* Amer. Mon. Micr. Journ., v. (1884) pp. 99-100. From Pop. Sci. Mon,
May 1884,
738 SUMMARY OF OURRENT RESEARCHES RELATING TO
attributed to the molecular action between solid and liquid bodies;
or, in other words, to capillary adhesion.
If we examine the under part of the pulvilli with a Microscope, we
shall see distinctly that it is furnished with numerous hairs, regularly
distributed. These hairs terminate, at their lower end, in a kind of
bulb, the form of which varies, whence flows an oily liquid that dries
slowly and does not harden for a long time. The minute drops left
on the glass by the hairs may be taken away, even after two or three
days have passed, without our having to moisten them, by simply
rubbing a piece of fine paper over them.
I have devised an apparatus for collecting these drops by cutting
a hole in a piece of board, over which I fix a glass slide. Turning
the board over so that the glass shall be at the bottom, I have a little
cell with a glass floor. With the aid of a piece of paper gummed
to the wings, I introduce a fly into this cavity in such a manner that
the pulvilli shall rest upon the floor. Then, putting the board under
the Microscope with the glass slide uppermost, we have the fly’s feet
under oureyes. The insect, struggling for liberty, places his pulvilli
against the glass, and leaves after each effort traces that may be
observed very distinctly, for they are perfectly visible in a good
light.
We may discover, whenever the feet of the fly come again in
contact with these tracks or minute drops, that they are composed of
a very liquid substance, for they spread quite readily on the glass.
We cannot admit, as some naturalists assume, that the liquid can hold
the club-shaped hair-ends by suction. If this were the case, the ends
would change shape during the suction, and would take the form of a
disk. The fly puts its feet down and lifts them up with an in-
comparable facility that would not exist if the limb were really acted
upon by the pressure of the air.”
Organs of Flight in the Hymenoptera.*—Dr. Amans has a further
paper on flying organs ‘in insects, and in the groups now studied he
recognizes as constant factors the following. The general form of
the machine must be a more or less elongated oval, with its widest
end directed forwards. 'The framework must have a solid floor with
more or less elastic walls, more or less united behind so as to form a
fixed transverse pivot-line; the walls must be sustained by a vertical
column, and there must be a roof movable on these walls around the
pivot-line, from before backwards and below upwards. The rotation
is effected by means of the wings.
The “schematic form of the wing” is that of an elastic triangular
surface, the breadth of which gradually diminishes from before back-
wards, and from base to summit, the latter being centrifugal. For
its articulation the wing must have a double articular surface at its
point of attachment, and the movable roof must articulate with the
apex of the angle of the dihedron. The surface in front of the point
of attachment must be one of pronation, that behind it of supination.
The motors are (a) forces that are elevating, retracting, and divari-
* Rey. Sci. Nat., xii, (1884) pp. 482-522 (2 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 739
cating ; (b) forces antagonistic to the preceding ; (c) propulsive, flexing
and depressing the anterior plane; and (d) forces which depress and
propel the posterior plane. The first two of these are inserted into
the roof and floor, the last two into the base of the wing. The motor
forces are the voluntary muscles, the actions of which are combined
with involuntary, that is, elastic forces: of the latter, the chief are
the resistance of the roof to the curvature caused by the former when
the wing is depressed, and the resistance of the anterior part of the
point of support to the flexion due to the muscles of group (c).
The author bases these conclusions on what he has seen in the
Orthoptera, Pseudo-neuroptera, and Hymenoptera.
Poison of the Hymenoptera and its Secreting Organs.*—G.
Carlet, in opposition to previous observers, finds that the venom-
producing apparatus of the Hymenoptera is always formed by two
distinct systems of glands, one of which has a secretion which is
strongly acid, and the other feebly alkaline. The two systems open
at the base of the spine, and the combined liquid is always acid.
Experiments made on the common house-fly showed that the sting of
a venomous Hymenopteron was always followed by the immediate
death of the fly, but that the inoculation of the product of either of
the glands does not result in death, or only in death after a long
interval. The successive inoculation ‘of the two secretions leads to
death shortly after the second inoculation, and we may suppose that
life ceases as soon as the two liquids have mixed. It is then clear
that the union of the acid and alkaline secretions is necessary for the
venom to have any fatal effects.
Development of Cerocoma Schreberi and Stenoria apicalis,t—
H. Beauregard communicates some facts as to the development of
certain insects allied to Cantharis; the larve appear to be melli-
vorous, and it is possible that they may live as parasites indifferently
in certain Hymenoptera. The larve, contrary to the habits of Epi-
canta and Macrobasis, as described by Riley, do not live on the eggs
of Orthoptera. It has been found that the larva of Cerocoma lives on
the honey of Colletes and of Osmia.
Other pseudochrysalids found in the cells of Colletes signata, and
presenting a very regular ovoid form, of a golden yellow colour, and
enveloped in a very fine iridescent pellicle, were watched through
the winter, and found in May to commence to undergo a series of
metamorphoses which ended in the appearance of the adult Stenoria
apicalis, which was found by Lichtenstein to be, in its earliest stages,
parasitic on Colletes fodiens. Here, again, therefore, we have evidence
as to the indifference which these parasites exhibit as to their choice
of a host. The history of development justifies the separation of
Stenoria from the true Sitaris.
Dipterous Larve.{—Dr. F. Brauer has published a valuable mono-
graph on this subject, the result of ten years’ labour.
* Comptes Rendus, xcviii. (1884) pp. 1550-1.
t Ibid., xcix. (1884) pp. 148-51.
¢ Denkschr. K. Akad. Wiss. Wien, xlvii. (1883) 100 pp. (5 pls.), Of. Amer,
Natural,, xviii. (1884) pp. 609-11.
740 SUMMARY OF CURRENT RESEARCHES RELATING TO
After lengthy remarks on the systematic relations of different groups
of Diptera, based on the larval characters, he states that the typical,
inherited feature in the entire group of Dipterous larve appears to be
the position of the brain, whether it is contained in a head-capsule, or
free, i.e. far behind the mouth or immediately behind the chitinous
capsule, supporting some of the mouth-parts, and containing the
cesophagus. Less important characteristics are then enumerated. A
very unsafe character is the number of visible body-segments.
The characters of the dipterous larve in general are laid down and
the value of the larval characters in classification discussed. A
tabular view of the nervous systems of the larval as compared with
the adult Diptera is followed by a section on the character of the
sub-orders and families which occupies the greater part of the work.
It is succeeded by short descriptions of a few larva of the families
Tabanide, Leptide, Dolichopide, and Empide.
Larve of North American Lepidoptera.*—A. Gruber gives a
description of the larve of some Papilionidz and Nymphalide ; scanty
as his material seems to have been, he thinks that the larve before
him give indications of the possibility of making out the genetic
relations of the species.
The first stage of the larve of the Papilionide is distinguished b
the constant possession of well-developed warts, on which there are
long sete that give a hairy appearance to the caterpillar. They are
longest on the most anterior and the most posterior rings of the body
and a correlation is apparent between the thoracic and the three last
abdominal segments. After each ecdysis the warts decrease in size,
and sooner or later disappear altogether; the smallest, or those on
the median segments, are the first to be lost. The function of these
warts appears to be that of providing suitable and prominent points of
attachment for the sete; it is to be noted that the warts are rudi-
mentary in proportion to the distinctness of the markings on the
caterpillar. It is these markings that have been seized upon by
natural selection, and the other characters, which have lost their
significance, have been gradually suppressed. When the warts do not
interfere with the markings, as in the case of larve with black trans-
verse bands, they do not completely disappear until the last ecdysis.
We may, therefore, suppose that the larve of the Papilionida
have been derived from forms which were indifferently coloured and
not strongly marked, and which possessed strong setigerous warts ; all
the larvee in their first and even in their second stage, resemble this
hypothetical primitive form. Numerous intermediate conditions are
to be observed between it and the conspicuously marked forms found
at the present time, and each larva more or less completely repeats,
at its ecdyses, the phylogenetic history of its species.
Further than this, we may suppose that those larve which retain
their warts longest are the oldest forms, or those that stand nearest to
the primitive form.
The Nymphalide present arrangements which are the opposite
* Jenaisch. Zeitschr. f. Naturwiss., xvii. (1884) pp. 465-87 (2 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 741
of what are seen in the Papilionide, for, in the first stage, the sete
are set on inconspicuous elevations of the integument; in the second
there are conical warts, and these increase in size with each ecdysis :
the warts of the Nymphalide are, therefore, not inherited, but
acquired structures; their armature becomes of great importance and
affects their external form.
The most primitive sete appear to be those which are long,
slightly curved, and finely toothed on their margin ; in the course of
development they become simply smooth or swollen at their base.
The author hopes that the suggestions he puts forth will be
examined by those who have access to a larger number of examples,
and justly remarks that the investigation would be very valuable and
interesting.
Drinking Habit of a Moth.*—E. D. Jones describes a remark-
able drinking habit of a yellow and black Brazilian moth (Panthra
pardalaria). He found these moths sitting on the wet stones in small
streams near San Paulo, sucking up the water in a continuous stream,
and letting it escape in drops from the abdomen. These drops fell at
the average rate of 50 per minute, and as near as he could judge of
their size, the total quantity of water which must thus pass through the
body of the moth in three hours must be a cubic inch, or about 200
times the bulk of its own body. Mr. Jones speculates on the possible
meaning of this and asks—* Can it be that the moth extracts nourish-
ment from minute particles of organic matter contained in the water ?”
He remarks, however, that the water of the streams appears very clear
and pure, and notes that the moths seem specially adapted for this
habit. ‘The tibiz of the hind legs are very thick, and are armed with
long hairs, which by their capillary action prevent the moth being
immersed in the water “I have often,” he adds, “seen one of them
knocked down by a little spurt of water splashing over the stone
on which it was standing, and it recovered itself almost immediately
without being wetted in the least,”
vy. Arachnida.
Michael’s British Oribatide.|—It would be difficult to say too
much in praise of this book which the Ray Society are fortunate in
being able to publish as one of their invaluable series, while this
Society may congratulate itself in numbering among its active members
an author who has produced a work which has required so much
labour and skill and so much perseverance, and which will rank as
one of the not too numerous standard works in the English language
devoted to sections of the Invertebrata, The author’s tribute to the
assistance rendered him by his wife, is an additional justification (if
any is required) for the resolution which he recently moved for the
admission of lady Fellows to the Society,
The classification of the Oribatide is fully dealt with, followed
* Proc. Lit. and Phil. Soc. Liverpool, xxxvii. (1883) pp. Ixxvi.—vii.
+ Michael, A. D., ‘British Oribatide,’ xi. and 336 pp. (3 pls.) 8vo. Ray
Society, 1884.
'
742 SUMMARY OF CURRENT RESEARCHES RELATING TO
by a chapter on their development and immature stages, the observa-
tions necessary for which were the most laborious part of the author’s
undertaking, involving the rearing of a large number of the micro-
scopic animals in confinement, and their careful watching and the
regulation of their hygrometic conditions every day for months!
They had indeed to be carried about with him on any journeys.
Amongst the habits of the Oribatide are enumerated their avoidance
of light, which increases so much the difficulties of observation, their
habit of carrying a portion of their cast skins and piling up dirt and
rubbish on their backs to form an artificial covering, or investing
themselves with a white substance. From the chapter which gives
very detailed directions on collecting and preserving, we have already
made some extracts.*
The remainder of the book deals with the anatomy of the exo-
skeleton and internal anatomy (pp. 110-190) and with the description
of genera and species (pp. 191-327). 31 plates, mostly coloured (some
of which have appeared in this Journal in connection with Mr.
Michael’s various papers), illustrate the text.
A type series of slides has been deposited by Mr. Michael in the
Society’s cabinet.
6. Crustacea.
Stomach of Podophthalmate Crustacea.{—In this important con-
tribution to our knowledge of the anatomy of the higher Crustacea,
F. Mocquard, after the ordinary historical review, points out that in
the Decapoda there are important differential characters, distinguishing
the Brachyura from the Macrura, but that, as is already known, the
so-called Anomura belong, some to the brachyurous and some to the
macrurous type. When we review all the families we find in every
natural one that the gastric apparatus is arranged on a special and
characteristic type.
In the Brachyura the mesocardiac piece is narrow and triangular,
while the pterocardiac ossicles are elongated and directed horizontally ;
in the Macrura, on the other hand, the former occupies the whole of
the transverse line of the superior cardiac wall, while the latter are
ordinarily shorter than in Brachyura and are set almost vertically.
Although it is true that the short-tailed forms never present the
characters seen in the gastric ossicles of the long-tailed, the converse
proposition does not hold good, for in such Macrura as have under-
gone some degeneration, the ossicles are formed on almost the same
type as in the Brachyura. The more detailed account of the differ-
ences between these two groups are set forth in the paper.
In passing from the normal Brachyura to the abnormal (or apteru-
rous Anomura), we observe a certain number of characters inter-
mediate between what are seen in the Brachyura on the one hand,
and the Macrura on the other; and it is to be noted that, on a con-
sideration of nothing but the arrangements of the parts of the gastric
skeleton, we should ascribe to them that intermediate position which
* See this Journal, ante, p. 635. + Tbid., p. 500.
{ Ann. Sci. Nat. (Zool.), xvi. (1884) 311 pp. (11 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 743
is commonly ascribed to them, after a study of their characters in
general.
Notwithstanding the numerous differences presented by different
groups, in the successive series of degradations which are to be
detected, it is possible to show that the gastric skeleton is never
modified except by change in the form or relations of its parts, by
their coalescence and disappearance ; nothing new is ever added, and
even when most degraded, the homology of the different parts can be
asserted almost with certainty. In other words, the gastric skeleton
of all the podophthalmate Crustacea is constructed on the same plan.
The author makes some remarks from a systematic point of view,
and urges that the importance of the characters of the stomach is to
be explained by the fact that it is not directly subjected to external
influences, and is much less exposed to the changes which result from
adaptations to environment than are the external organs. These
characters then, are of great value in determining the relationships of
genera with a different external appearance.
Mocquard describes the arrangement of the muscles which move
the various ossicles, and facilitates the comprehension of his descrip-
tion by his figures; he finds that, at the moment when the gastric
muscles contract the median tooth moves forwards, and the anterior
ends of the lateral teeth approach one another; when the gastric
muscles relax the apparatus is brought back to its position of equi-
librium, by the elasticity of its articulations, and by the action of the
cardio-pyloric muscle. When the gastric apparatus is acting, the
food tends to be driven upwards, but its passage is prevented by the
projections on the urocardiae ossicle. The medio-inferior tooth,
though with the form, has not the function of a tooth ; its conforma-
tion has no relation to that of the median tooth, and one of the two
may vary in form, without the other doing so likewise.
The author agrees with Cuvier in thinking that the gastric muscles
are voluntary in nature.
The concluding chapter deals with the stomatogastric nervous
system, the knowledge of the distribution of which is thought to
throw a new light on its physiological activity. While some authors,
such as Meckel and J. Miiller, have compared it to the great sympathetic
of vertebrates, others, such as Newport and Blanchard, have compared
it to the pneumogastric nerve. The latter view can only be justified
by showing that the stomatogastric system presides over the functions
of general sensibility and involuntary movement ; as a matter of fact,
however, in the Crustacea, the fibres that pass to the muscles of the
cesophagus and labrum are clearly voluntary, and the same is almost
certainly true of the branches that go to the motor muscles of the ~
gastric apparatus, and possibly also of those that supply the dilatators
and constrictors of the stomach ; some of those that go to the labrum
seem, moreover, to have a gustatory function. It is possible, how-
ever, that the different roots of the stomatogastric have different
functions, and that, when united, they form a mixed trunk more com-
plex even than that of the vagus after its union with the internal branch
of the spinal. No observations on this point have as yet been made,
744 SUMMARY OF CURRENT RESEARCHES RELATING TO
Significance of the Larval Skin in Decapods.*—H. W. Conn
discusses the phylogenetic significance of the peculiar structure
inclosing embryos of Crustacea known as the larval skin. This
skin being probably of no physiological importance, is therefore
particularly valuable in its morphological significance.
A number of new types of larval skin are described (Callinectes,
Sesarma, Pinnotheres), and it is shown that there is a complete and
graduated series beginning with a form like Panopeus, where the
larval skin is a highly complex structure with many feathered spines,
and ending in a form like Pinnotheres, where the cuticle is nothing
more than a larval covering with no spines. In general also it is
found that the more complex larval skin is found in crabs, which
stand low in classification, while the simple larval covering is found
in more highly organized Brachyura ; a condition of things just as
we should expect from the consideration that this structure represents
the ecdysis of some stage in the crab development earlier than the
zoea. It is further shown that such an earlier stage was probably a
protozoea and that we, therefore, have here strong evidence that this
stage was formerly included in the ontogeny, and therefore in the
phylogeny of the Brachyura. Finally it is argued that evidence is
here obtained tending very strongly to show that the Decapod zoea is
simply a larval form which has neyer been represented in the phylo-
genetic history of the group, contrary to what has been claimed by
Miiller, and later in a different form by Balfour.
New or Rare Crustacea.{—In his 34th article on this subject
M. Hesse describes five new Crustacea belonging to the order which
he has called that of the Rostrostomata; like the Siphonostomata,
they are found on the skins of the Squalide, but, unlike them, they
have not a rigid tubuliform mouth by means of which they can
penetrate the thick skin; the mouth is rather obtuse and soft, and
the animals, therefore, make their way into the branchial cavity, where
they are sheltered and early obtain a rich supply of food.
The new species, of which the females are alone known, are called
Kroyeria galei vulgaris, Eudactylina squatine angeli, Eudactylus
musteli levis, E. charcharie glauci, and Pagodina charcharie glauci.
The author concludes with some observations on the systematic
position of these species.
: Vermes.
New Type of Hirudinea.t{—MM. Poirier and A. T. de Rochebrune
describe a new type of Hirudinea which they found attached not
only to the mucous membrane of the mouth of Crocodilus vulgaris,
Cataphractus, and Leptorhynchus, but also on the lingual papille of
Cymnoplax egyptiacus, and in the pouch of Pelicanus and Onochrotalus.
In external appearance it has a general resemblance to Branchiobdella.
Attached to the very delicate rectum are four pairs of very sinuous
* Stud. Biol. Lab. Johns-Hopkins Univ., iii. (1884) pp. 1-27 (2 pls.). Cf. this
Journal, ante, p. 226.
+ Ann. Sci. Nat. (Zool.), xvi. (1884) 18 pp. (8 pls.).
{ Comptes Rendus, xcviii. (1884) pp. 1597-1600.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 745
tubes, which are set between the dorsal surface of the animal and
-the ceca. The appendages of the digestive tube are continued into
the branchiz, and the tract is also remarkable for the possession
of large unicellular glands with finely granular contents; these form
the salivary glands.
The male generative apparatus is composed of four pairs of ovoid
testicles, which are placed in the last four branchiate segments; the
efferent ducts unite, on leaving the epididymis, into a short azygos sper-
matic canal, which passes into a large muscular pouch, into which the
very large penis can be retracted. The female organs consist of a pair
of very long pyriform ovaries, and of two delicate oviducts which pass
into an inconspicuous uterus. The circulatory system presents some
remarkable characters. There is no dorsal vessel, but there are two
pairs of lateral vessels, which are superposed and send branches into
the branchial outgrowths; the superior lateral vessels, which may be
considered as being arterial, communicate with one another in each
ring by an annular vessel which sends fine ramifications to the surface
of the skin; posteriorly, these two lateral canals bifurcate and unite
by the branches thus formed ; they here give off a number of ramifi-
cations which extend over the lower surface of the sucker, and pass"
into a double circular vessel which extends round the edge of the
sucker. There is a median ventral vessel which envelopes the nervous
system and gives rise anteriorly to a ring which communicates with
the lateral vessels, and posteriorly to a number of branches which
open into the vessels of the sucker. The nervous system has a close
resemblance to that of Clepsine; there are two very large, cup-shaped
orange-coloured eyes. The integument, especially in the anterior
region, is very rich in glandular cells.
The new genus to be instituted is called Lophobdella, and the
species L. quatrefagesi ; it is found in Senegambia and the rivers of
Africa. Its peculiarities require the formation of a new family, to
be called the Lophobdellide, and placed near the Rhynchobdellide.
Structure of the Branchie of Serpulacee.*—Dr. L. Orley gives
a detailed account of the histology of the gills in the Serpulacee.
His results may be stated as follows :—
In Serpula the gill-threads are borne upon two curved lamellar
processes, one on cither side of the head; these are united by a cross
piece; one or two of the gill-threads are modified into a stalked
opercular plate; this latter in some species serves as a chamber for
the development of the ova, and is generally regarded as serving to
close the tube of the animal when it is retracted. Its structure,
however, points to the conclusion that it may also serve as a respi-
ratory organ (the other gill-filaments with which it is homologous
being chiefly tactile). It receives a vast number of capillaries which
branch repeatedly towards the distal end of the “cup,” and end in
ampulla-like dilatations; the advantage of such a structure to
the animal must be great, since it is enabled to protect itself by
closing the operculum, and at the same time the process of respiration
* MT. Zool. Stat. Neapel, v. (1884) pp. 197-228 (2 pls.).
Ser. 2.—Von. IV. 8D
746 SUMMARY OF CURRENT RESEARCHES RELATING TO
can go on; the operculum may perhaps have been formed by the
concrescence of a series of gill-branches arranged in a circle round
the tip of the gill-filament.
In Sabella the gill-filaments differ from those of Serpula by the
presence of a cartilaginous rod and a portion of the longitudinal
muscle-layer of the body which is prolonged into them in close con-
nection with this skeletal rod.
The paper concludes with a discussion concerning the homologies
of the gills in Serpulacee with the gills of Vertebrata, which is
believed to exist by some; the author, however, does not con-
sider that there is any homology or even analogy between the two
structures.
Structure and Development of Fresh-water Dendrocela.*—The
studies of J. Jijima are based chiefly on Dendrocelum lactewm,
Planaria polychroa, and Polycelis tenuis (n. sp.). Commencing with
a description of the cilia, he states that, in adult forms, these are not
developed over the whole surface of the body, but are absent from
certain regions; they are particularly well developed at two points at
the anterior margin of the head, where they form a tuft of long and
constantly moving hairs; their function would appear to be sensory..
Some shorter immobile cilia are found on the median portion of the
cephalic margin, and among these there are some which are twice as
long, and either stand separately or arise from a common base; they
may be regarded as comparable to sete. The absence of cilia from
the sides of the body may be ascribed to the influence of parasitic
Protozoa. It would seem that the cilia on the back of the Geoplana
and other terrestrial Triclades, are more delicate than those on the
ventral surface, and are, therefore, more easily destroyed in the
process of preservation.
The author was, like Kennel, unable to detect the unicellular
epidermal glands seen by Moseley, and is led to doubt their presence ;
a certain relation was observed between the rhabdites and the
characters of the cells of the epidermis; the smaller size or number
of the former being associated with a greater wealth of finely glanular
protoplasm in the latter. Jijima finds that there is a very re-
markable relation between the cells and the basal membrane on
which they are placed; for the former give off a number of fine pro-
cesses; these are best studied in Planaria polychroa, where they appear
to be formed by fibrils, which are nothing else than direct proto-
plasmic processes of the cells of the epidermis; there is little doubt
that there is an organic connection between the epithelium and the
interior of the body.
The rhabdites, which are described in some detail, do not seem to
be imbedded in the epithelium, but in the peripheral cells of the
mesenchym. Lach cell gives rise to several rhabdites, which are
at first small and round, but which soon elongate. When they have
reached their definite size they break through the cell-wall, which
appears at last to be absorbed, and wander through the connective
* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 359-464 (4 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 747
tissue and the basal membrane, either separately or by groups, into
the epidermal cells, where they take up their definite position. There
appear to be a larger number of rhabdites in more sensitive than in
less sensitive parts of the body. The basal membrane is more or less
well developed in all Turbellarians. The characters of the musculature
are discussed in detail, and the differences between the three species
examined are pointed out.
The mesenchym contains imbedded in itself unicellular glands,
which are most numerously developed behind the brain, and above
and below the enteric canal. Their function is either mucous or
salivary ; but it is by no means certain that the latter are comparable
to the similarly named glands of higher animals. In young embryos
the space between the epidermis and the enteric epithelium is occu-
pied by a solid mass of connective-tissue cells, which are partly
massed into syncytia, and are partly separated by cell-boundaries. In
the adult the arrangement is very different, owing to the appearance
of a larger number of pseudo-ccelomic spaces, which communicate with
one another, and force the nuclei away from one another, and so give
rise to branching cells of connective tissue and a general appearance
of reticulation. In the living animal the lacunar spaces are probably
filled with the so-called perivisceral fluid, which possibly serves as a
carrier for the nutriment prepared within the enteric cells. Dendro-
celum lacteum has, as its name implies, none of its connective tissue
pigmented, as is the case in a number of other forms.
The author confirms in many points the descriptions given by his
predecessors as to the characters of the digestive organs; in D.
lacteum he finds that there are 26-34, in Pl. polychroa 22-28, and in
Pol. tenuis 15-19 pairs of lateral branches to the intestine, of which
10-15, 9-13, and 4-6 respectively belong to the primary trunk of the
gut. All but those at either end branch dichotomously. His account
of his own observations on the excretory organs is prefaced by a
statement of what has been done by recent observers; the point to
which he himself directs express attention is the undoubted fact of
the presence of cilia in the lumen of certain capillaries; in the
median part of the body they are best developed, and take a coiled
course; their movement is definite in direction, and these ciliated
vessels have nothing to do with the ciliited infundibula. Many of
these vessels are so fine that, were it not for their cilia, they would
be invisible. The ciliated infundibula are not numerous in, at any
rate, young specimens, and are often widely separated from one
another. The presence of excretory vacuoles was recognized, and
they were seen to be, like the vacuoles of the Protozoa, clear during
life; they give some indications of containing products of uric
excretion.
After a very detailed description of the generative organs, the
nervous system is taken up. This was studied by the light of Lang’s
investigations, the general results of which are fully confirmed.
Jijima had no difficulty in convincing himself of. the existence of a
plexus of fine nerves on the dorsal surface, lying just beneath the
inner longitudinal fibres of the dermal musculature. As in other
oD 2
748 SUMMARY OF CURRENT RESEARCHES RELATING TO
Platyhelminths, there are two longitudinal nerve-trunks which unite
posteriorly, after gradually increasing in size. The transverse com-
missures go directly from one trunk to the other, and often branch
and anastomose with their neighbours. Both the commissures and
the lateral nerves give off a number of fine branches ventrally. The
brain of Planaria polychroa stands at a lower level than that of D.
lacteum or Pol. tenuis, owing to the want of concentration of the
sensory nerves into anterior cerebral lobes. The eye of P. polychroa
is described as consisting of a pigment-goblet, an optic cone, and an
optic ganglion. The first is formed of compact pigment-granules,
and has its orifice directed outwards and upwards. Anteriorly to this
opening there is a collection of nervous substance, surrounded by a
number of nuclei, which appear to belong to ganglionic cells.
The author was unable to observe the impregnation of the ovum,
and thinks it likely that the spermatozoa are to be found in the
albuminous fluid of the cocoon. Directive corpuscles were not
detected, probably because the ova have no investing membrane, so
that their presence was obscured by the contents of the cocoon. ‘The
layer of fused cells, which early becomes developed, seems to be due
to the metamorphosis of the peripheral cleavage-spheres. The em-
bryonic pharynx is formed by the elongation of some of the endo-
dermal cells, which become converted into muscular cells, and surround
a central group of cells, which soon afterwards begins to make its
way to the surface; clefts appear in this mass and lead to the
gradual appearance of a lumen. This pharynx is only provisional,
and is at about the twentieth day replaced by the one which is
possessed by the adult. The author has, unfortunately, no ob-
servations to record on the mode of development of the excretory
organs, or of the finer parts of the nervous system.
Classification of the Rotifera.*—Dr. C. T. Hudson points out
what seem to him to be the chief faults in the systems of Ehrenberg,
Dujardin, Leydig, and Bartsch, and proposes the following arrange-
ment of the Rotifers in well-marked and fairly natural groups.
ORDER I. RHIZOTA.
Fixed forms; foot attached, transversely wrinkled, non-retractile,
truncate.
Fam. 1. FLoscunARIADZ.
Mouth central; ciliary wreath a single half-circle above the
mouth ; trophi uncinate.
Fam. 2. Menicertapz.
Mouth lateral; wreath two marginal curves nearly surrounding
the head, with mouth between; trophi malleo-ramate.
* Quart. Journ. Micr. Sci., xxiv. (1884) pp. 335-56 (15 figs.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 749
ORDER II. BDELLOIDA.
That swim and creep like a leech; foot retractile, jointed, tele-
scopic, termination furcate.
Fam. 3. PHILODINADZ.
Trochal disk two transverse circular lobes ; wreath two marginal
curves on each lobe with mouth between ; or trochal disk of one lobe
ventrally furred with cilia; trophi ramate.
ORDER III. PLOIMA.
That only swim.
* Tlloricated.
Fam. 4. Hypatinapz@.
Trochal disk transverse with ciliated prominences; wreath double ;
trophi malleate ; brain small, not sac-like ; foot furcate.
f
Fam. 5. SynonmrTapz.
Trochal disk rounded ; wreath of interrupted curves, surrounding
the head ; trophi virgate; foot absent, or minute.
Fam. 6. Norommatapz.
Trochal disk oblique; wreath of interrupted curves and clusters ;
trophi virgate or forcipate ; brain large, sac-like ; foot furcate.
Fam. 7. TRIARTHRADZ,
Trochal disk transverse ; wreath single, marginal ; trophi malleo-
ramate; foot absent.
Fam. 8. ASPLANCHNADA.
Trochal disk rounded ; wreath single, marginal ; trophi incudate ;
intestine, anus, and foot absent.
** Toricated.
Fam, 9. Braonwionrp™.
Trochal disk transverse with ciliated prominences ; wreath single,
marginal ; trophi malleate ; lorica entire, simple; foot transversely
wrinkled, wholly retractile, two-toed or absent.
Fam. 10. Preropinapz.
Trochal disk two transverse circular lobes; wreath on each
double, marginal ; trophi malleo-ramate ; foot transversely wrinkled,
wholly retractile, ending in a ciliated cup.
750 SUMMARY OF CURRENT RESEARCHES RELATING TO
Fam. 11. EvoHLAnipa.
Trochal disk rounded ; wreath in interrupted curves and clusters ;
trophi sub-malleate or virgate; lorica im two parts, meeting in a
furrow, or entire with additional pieces : foot jointed, feebly retractile,
not telescopic or transversely wrinkled—furcate or stylate.
ORDER IV. SCIRTOPODA.
That swim with their ciliary wreath, and skip by means of hollow
limbs with internal locomotor muscles.
Fam. 12. PepAionip™.
Trochal disk transverse ; wreath two marginal curves with mouth
between ; trophi malleo-ramate; foot replaced by two posterior
ciliated processes.
GENERA.*
1. Fuoscunariapz .. Floscularia, Stephanoceros.
2. MeuicertaDH .. Melicerta, Limnias, Micistes, Cephalosiphon,
Lacinularia, Megalotrocha, Conochilus.
3. Painopinapbz = ..._~—«- Philodina, Rotifer, Callidina.
4, HyDATINADE .. Hydatina, Rhinops.
5. SyncpmTapH .. Syncheta, Polyarthra.
6. Norommatapz .. Notommata, Diglena, Furcularia, Scari-
dium, Pleurotrocha, Distemma.
7. TriartHraDz .. ‘Triarthra.
8. ASPLANOHNADZ .. Asplanchna.
9. Bracnionipz .. Brachionus, Noteus, Anurea, Sacculus.
10. Preropinapz .. Pterodina, Pompholyx.
11. EvcHLanipz .. Huchlanis, Salpina, Diplax, Monostyla,
Colurus, Monura, Metepidia, Stephanops,
Monocerca, Mastigocerca, Dinocharis.
12. Pepauionipz .. Pedalion.
Echinodermata.
Constitution of Echinoderms.t—C. Viguier, after a reference to
the belief that Echinoderms are radiated animals, discusses the
view propounded by Duvernoy and forcibly enunciated by Hackel,
against which he has already raised some objections, and side by side
with which he now pits the doctrine of Perrier taught in his work
on ‘ Colonies Animales.’ According to the view of Perrier, the Echino-
derm is indeed a colony, but, instead of being formed of five equiva-
lent individuals (antimeres), it consists of five reproductive individuals
grouped around a nutrient individual; these may coalesce in various
proportions. All Asteroidea are fragile, and all enjoy the power of
* “The principal ones; several of Ehrenberg’s are omitted for various reasons
that cannot here be detailed, and the genus Notommata, though the name is
retained, is here supposed to have lost a large number of Ehrenberg’s species.”
+ Comptes Rendus, xcviii. (1884) pp. 1451-3.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. Tol
repairing broken arms; this rupture is often followed by a process of
reproduction, numerous cases of which are already known. These
facts may be as easily explained by the theory of Hackel as by that
of Perrier, but there are others which can only be explained by the
latter.
The hard parts around the mouth are, it is well known, very
difficult to homologize with the ambulacral and adambulacral ossicles
of the arms; but it is necessary to do this, if we regard the disk as
nothing more than a fused part of each of the arms. On the other
hand if either disk is an independent piece no homology is possible.
We sometimes find specimens in which a broken arm becomes
bifurcated at its free end ; if the buccal angles were merely formed by
the union of the pieces of two neighbouring arms (as ought to be the
case on Hiickel’s theory) it is difficult to see why the angle of bifurca-
tion should not be formed in just the same way. On the other hand,
if the peristomial skeleton belongs to a central individual it is evident
that an arm could not produce along its own course pieces similar to
those of the central piece—the odontophors or the teeth. Between the
oral angle and the angle of bifurcation at the free end differences may be
observed in the spines, which in the latter are exactly like the adam-
bulacral and different from the longer ones found at the angle of the
mouth ; the brachial angle is formed by adambulacral pieces, which
are very different from the large truncated teeth of the peristome ;
and, lastly, the odontophor which is so characteristic a part of the
disk, is altogether wanting at the angle of the brachial bifurcation.
The author adduces photographs in support of these statements.
Pourtalesia.*—Professor §. Lovén, the veteran author of the
‘ Etudes sur les Echinoidées, has made another important contribu-
tion to the morphology of the Echinoidea, based on a study of the
characters of the remarkable deep-sea genus Pourtalesia,
The first chapter deals with the general form of the skeleton,
which, as in all Kchinids, is a hollow sac inclosing the visceral
organs, and constituted by three distinct systems—ambulacral, peri-
somatic or interradial, and calycinal or apical. The mode of numbering
suggested in the ‘ Etudes’ is here again made use of. Whenever this
skeleton has been accurately studied it has been found that its con-
stituent elements are, in reality and fundamentally, arranged bilaterally
and symmetrically on either side of the mesial plane, indicated by its
antero-posterior axis. The archeonomous or old-fashioned type of
the Clypeastride as well as the neonomous or new-fashioned Spatan-
gide give distinct indications of the bilateral form of the adult.
Though more difficult to detect, this bilaterality obtains also in the
ancient Cidaride, and we have here “another instance of the validity
of one of the laws more than once ascertained to underlie evolution,
namely, that structures which are to be gradually but forcibly worked
out during the course of geological ages into specialized and highly
characteristic features, are virtually present within the fabric of the
* K. Svenska Vet. Akad. Handl., xix. (1883) 95 pp. (21 pls.) (written in
English).
a2, SUMMARY OF CURRENT RESEARCHES RELATING TO
earlier forms, though dormant, and, as it were, lying in abeyance, and
to be detected only by a close scrutiny.”
The general form of Pourtalesia is unlike that of any other known
Echinid ; it has the form of an inverted short-necked bottle ; from the
side the anterior line is seen to be bluntly truncated, while the dorsal
surface is marked posteriorly, by a deep depression, behind which
there is a truncated caudal prolongation. Anteriorly the test is
suddenly bent inwards and backwards, so as to form a deep ovoidal
recess leading to the mouth. It would seem as if “this anomalous
configuration’ were due to “the dorsal portion of the body having
moved forwards beyond the normal measure, and s0 as to leave behind
the subanal part of the ventral portion, and as though its forepart
produced into a rostrum projecting ventrally and compressed from
both sides, had been drawn, by invagination, into the peritoneal
cavity.”
The perisomatic portion is next dealt with, and here perhaps we
have the most anomalous condition of parts, for it is found that two of
the interradii unite in the middle line and so form a continuous
broad ring passing round the middle of the body; this arrangement
appears also to be found in Spatagocystis, but it is only seen in
P. jeffreysi and P. laguncula among the species of the genus Pourtalesia ©
as defined at present. Lovén makes the interesting remark that
“once before, early in Mesozoic time, for a while and not unlike a
trial soon given up, a structure resembling this was seen in the
Collyritide, but imperfect, the ring being open ventrally and closed
dorsally only.” As it obtains in P. jeffreysi, the author thinks that
the radiate disposition of the skeletal elements is destroyed in an
essential degree, “ and a tendency betrays itself towards an annular
differentiation. of the bilaterally symmetrical constituents of the
cylindroid skeleton.”
The peristome likewise presents us with some very extraordinary
characters; the structure of which leads us to think “ that what is
going on here may be looked upon as the first move, so to speak,
towards forming a rudimental mouth, a cavum oris, the invaginated
parts of which, if they were flexible and provided with muscles, might
be protruded like a proboscis.” Without here going into details we
can only say that the author establishes his proposition that the joint
participation of the ambulacra in the formation of the peristome, and
the uninterrupted sequence of their plates does not obtain in the genus
under consideration.
The characteristic sensory organs (spheridia) first detected by
Lovén in the region of the mouth of Echinids, are not, as in most, _
arranged in Pourtalesia in all the five ambulacra, but are absent from
No. III., or that which is anterior and odd. In Pourtalesia, however,
the ambulacrum in question is raised above the level of the peristome,
so that we see that “of whatever nature the special changes in the
surrounding water may be that their ciliated epithelium has to watch
for, these changes seem to be of essential moment to the animal, solely
when they take place in the vicinity of the mouth, or between the
under surface and the ground on which the animal has to find its food.”
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. (533)
The author next enters on an elaborate account of the structure
of the pedicels of the Echinoidea, into the details of which our space
prevents us following him.
The next chapter deals with the important subject of the calycinal
system, which he defines as consisting of a central ossicle, five costals,
and five radials; he urges with much point the value of using these
terms, and says truly that, when we know more “ the final terminology
will come of itself.” The differences between the Crinoid and the
Echinoid organization are sharply pointed out, and it is shown that
in the latter the system “is rendered, to no small extent, a disputed
ground, each of these (generative, water-vascular, anal) organs tend-
ing to penetrate its substance and gain access to the surrounding
water.” Tiarechinus, with its enormous calyx, appears to be the most
antique of Echinoids. While a number of forms retain a stable
relation of the parts we find that, when this is disturbed, the anal
orifice is the first to alter its position; it is followed by the
madreporite and generative pores, but the eyes remain stationary.
The various stages of changes are traced in the most interesting and
instructive manner, and the whole history thus philosophically
summed up. “A large and powerful structure, closely specialized
for a function of fundamental importance in the economy of
some remote ancestral type, is inherited, in an early state, by a
descendant in which, from a total change in the mode of life, the very
purpose no longer exists for which it was originally contrived, and to
which its parts were adapted. It long retains certain marked features
which even to this day reveal its origin, but, unlike its crinoidean
sister-structure which, with functions unaltered, multiplies its com-
ponents—it remains simple as from the beginning, and, superfluous
as it has become, gradually declines in intrinsic vigour, and is given
up to subserving activities that had no share in its previous existence.
Invaded by contending organs and yielding to their various ten-
dencies it has its parts deeply modified and even to some degree
suppressed, and, although still true to its type, and asserting, so to
say, its unimpaired independence by redintegrating its injured frame,
it dwindles, nevertheless, from age to age in every succeeding form,
and is seen to fall into decay and dismemberment and to lose one by
one its characteristics, till at last little remains of its original
constitution.
In trying to sum up the characters of the Pourtalesiadw the
author feels the difficulty that the species which he has been able to
study most completely, P. jeffreysi is of a more advanced character
than the rest, but justly remarks that “this is not the first occasion,
nor will be the last, when a species that chances to be the most
familiar to us is put forward as the type of its kind.” The general
form of the skeleton is subcylindroid, truncated anteriorly, tapering
posteriorly ; there is a deep infrafrontal recess and a rudimentary
buccal cavity. Bilateral symmetry is highly developed; the peri-
somatic system predominates, while the calycinal is verging on decay.
The breach of continuity in two of the ambulacra is without parallel
among the members of the class. Like the Echinoneide they are
754 SUMMARY OF CURRENT RESEARCHES RELATING TO
alone among the neonomous Hchinoids in having homoiopodous
pedicels, none of which are disciferous or converted into respiratory
leaflets. The spines are Spatangean in characters. They do not
attain to the level of the Spatangidz owing to the frequent loss of the
organ of vision as well as by the simplicity of their pedicels. By
some of their characters they point, though remotely, towards animals
of another and higher type, animals of annulose differentiation.
They are found in all oceans, and, on the average, at a depth of
2900 metres.
As to the origin of the deep-sea fauna Prof. Lovén utters these
pregnant sentences: “ In the adult state most of the marine Evertebrates
remain at their native station, wandering within its precincts. Their
embryonic and larval age is their period of dispersal. Of numerous
littoral forms, of different classes, tribes, and orders, currents must
occasionally carry away the free-swimming larve ... . far into the
sea, and during the course of succeeding generations early stages of
many a species will in this way have reached the wide ocean. There
they will have sunk, their development accomplished all through
depths full of danger and more and more uncongenial, and a few of
them will have settled on the bottom of the abyss, and fewer still will
have come to thrive there. Among these some will long have their
original character, and but slowly been modified, while others
will have exhibited a latitude of variation unknown or rarely seen
where they came from, but upon the whole there will be reasons for
assuming the less altered forms to be new comers, the more deviating
to be old inhabitants of the deep.”
Anatomy of Larval Comatuie.*— Dr. P. Herbert Carpenter
closely criticizes some of the results lately published by Perrier.
He expresses his doubts as to the single curved water-tube of the
“ cystid-phase”” opening to the exterior by a pore on the wall of the
body, and inclines rather to Ludwig’s exact account of the primary
water-tube as a dependence of the water-vascular ring opening into
a section of the body-cavity, into which the primary water-pore,
which pierces the oral plate, also opens. He doubts also the
continuity of the pore and tube in later stages of the larva.
“ The most startling statement” on the part of Perrier is that the
plexiform gland of Crinoids corresponds, not with the ovoid gland of
Star-fishes and Urchins, but with the stone-canal of these echinoderms.
The ground for this statement can hardly be histological, and it is
difficult to imagine what it may be. The relations of the axial organ
to the cirri can hardly be seriously maintained, unless Perrier will
show that the cirrus-vessels are radial and derived from the cavities
of the chambered. organ. Dr. Carpenter reiterates the expression of
his hope that Perrier will publish more complete accounts and
illustrate them by a number of figures.
* Quart. Jaune Micr. Sci., xxiv. (1884) pp. 319-27.
+ See this Journal, ante, p. 389.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ios
Ccelenterata.
Notes on Meduse.*—C. Keller has some observations on Coty
lorhiza tuberculata, which appears at certain periods in the Mediter-
ranean, and the habits of which invite the question, what are the
causes of its regular migration, and whence does it come? From
the series of observations which the author was able to make he
was led to conclude that it is highly probable that this Medusa is
a true deep-sea form, which only comes to the surface for a time, and
spends most of its life in its sessile condition on the floor of the sea.
The cause of the migration appears to be associated with reproduc-
tion, the nurses being littoral, the young Meduse deep-sea forms,
so that the sexualiy mature animal rises to the surface and lives
pelagically. With reference to the theories that may be based upon
these facts Keller quotes Carl Vogt, who has lately expressed his
belief that the class Hydromeduse has arisen from two different
stocks, one of which has produced the Acraspedota and the Scypho-
stomata, the other the Craspedota, Siphonophora, and hydroid polyps,
and who, further, has expressed his belief that fixed and parasitic
creatures are always produced by special adaptation from forms that
were primitively free. Though this, of course, is not true of Comatula,
yet we must remember how infinite are the powers of adaptation, and
not summarily reject it as not applicable to the Medusz.
The yellow cells of C. tuberculata are next discussed, and the
author declares his agreement with the views of Geddes and of
Brandt that the bodies are algar in nature, and thinks that the
symbiosis is explicable on the supposition that the cells in question
are found only in the pelagic generative forms, which demand a
larger supply of oxygen.
A new Medusa—Orchistoma agaraciforme—the first species of the
genus found in Europe (Mediterranean), is next described. As the
development of the Orchistomide is as yet altogether unknown, it is
interesting to learn that Keller has found some young specimens; it
_was found that the gonads are only apparently canular, and that they
really arise from a gastric outgrowth, a condition as yet unique
among the Thaumantide or Leptomeduse. There appears to be a
considerable amount of metamorphosis ; the most important changes
obtaining in the radial canals, which increase in number; in the
gastric cavity, which diminishes in size; and in the proportionately
late development of the large gastric stalk.
Revision of the Madreporaria.j—Prof. P. M. Duncan gives a
revision of the families and genera of the Sclerodermic Zoantharia,
Ed. & H. or Madreporaria (M. Rugosa excepted). Since Milne-
Edwards and Haimes’ work of 1860, no systematic revision of the
Madreporaria has appeared, while since then a great number of new
genera have been founded; hence the necessity for a revision has
arisen, and more especially in consequence of the morphological
researches of Dana, Agassiz, Verrill, Lacaze-Duthiers, and Moseley.
* Recueil Zool. Suisse, i. (1884) pp. 403-22 (1 pl.).
+ Journ. Linn. Soe, Lond. (Zool.), xviii. (1884) pp. 1-204.
756 SUMMARY OF CURRENT RESEARCHES RELATING TO
In the present revision the sections Aporosa and Perforata remain,
but shorn of some genera; the old family Fungide becomes a section
with three families, two of which are transitional between the sections
just mentioned. The section Tabulata disappears, some genera being
placed in the Aporosa, and the others are relegated to the Hydrozoa.
The Tubulosa cease to be Madreporarian. Hence the sections treated
are Madreporaria Aporosa, M. Fungida, and M. Perforata. The
nature of the hard and soft parts cf these forms is considered in
relation to classification, and an appeal is made to naturalists to
agree to the abolition of many genera, the author having sacrificed
many of his own founding. The criticism of 467 genera permits 336
to remain, and as a moderate number (36) of sub-genera are allowed
to continue, the diminution is altogether about 100. The genera are
grouped in alliances, the numbers in families being unequal. Sim-
plicity is aimed at, and old artificial divisions dispensed with. There
is a great destruction of genera amongst the simple forms of Aporosa,
and a most important addition to the Fungida. The genera Stder-
astree and Thamnastre are types of the family Plesiofungida, as are
Microsolenia and Cyclolites of the family Plesioporitide. The families
Fungide and Lophoseride add many genera to the great section
Fungide. There is not much alteration in respect of the Madre-
poraria Perforata, but the sub-family Eupsammine are promoted to a
family position as the Hupsammide.
Prof. Duncan also describes * a new genus of recent Fungida,
Family Fungine Hd. and H., allied to the genus Micrabacia, and
which he names Diafungia. There is one species, D. granulata.
Porifera.
New Gastreades from the Deep Sea.j—Prof. E. Hiackel has
found among the collections of the ‘ Challenger’ organisms which
agree in the following characters; they live at the bottom of the sea
(in rare cases littorally, in the majority at great depths) and have a
firm skeleton formed of the substance there found, which they unite
into a solid cement by means of a small quantity of organic cementing
matter ; some of these skeletons formed quite a museum of Radiolaria,
consisting as they did of the most delicate shells of several hundred
species. The skeletons are either external or internal; the former
being due to the secretion of mucus from their outer surface, while
in the latter the foreign bodies were taken into the ectodermal cells.
In the former the secretion contains no cell-nuclei, in the latter they
consist distinctly of protoplasm, in which a few, or in rare cases,
a number of nuclei were to be found; we have then here to do with a
more or less modified syncytium. The organisms vary much in
form and size, the smallest being from 1-3 mm. in diameter, the
largest from 80-120. The organisms that form the cemented skeleton
may be either Protozoa or Metazoa; the former are, in a few cases,
colossal Lobose, allied to Difflugia; in many cases they are true
Rhizopoda, and the majority Thalamophora.
* Journ. Linn. Soc. Lond. (Zool.), xvii. (1884) pp. 417-9 (1 pl.).
+ SB. Jenaisch. Gesell. f. Med. u. Naturwiss., 1883 (1884) pp. 84-9.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. fiw
The cemental Gastreades fall into two groups, which have the
same relation to one another as have the Ascones to the Leucones
among the Calcispongiz. In the simple and phylogenetically older
forms, the wall of the gastric tube is thin and solid, but in the
further developed it is thicker and traversed by gastric canals. The
former, allied to the already described Haliphysema and Gastrophysema,
are either branched (Dendrophysema) or plexiform (Clathrophysema).
The latter belong to a new group called the Cementaria ; resembling
many Dysidiide, they are distinguished by the complete absence of
ectodermal pores, so that the water only enters the irregular canal-
system (the spaces of which are completely or partly invested by
endodermal flagellate epithelium) by the mouth-orifices. In the
endoderm there are scattered ovarian cells. Ccmentascus forms
simple tubes, with a single oral orifice ; Caementoncus has several
orifices and is irregular in form ; Cementissa forms flat lobate crusts ;
Cementura branched creeping or dendriform masses with several
mouth-openings. Hiackel thinks that the Orthonectida are allied to
the Cyemaria, and that the Trichoplax of F. E. Schultze is a perma-
nent Discogastrula form.
Siliceous Spicules of Sponges.*—J. Thoulet has examined the
structure and other characters of the spicules of various sponges
collected during the last cruise of the ‘Talisman. They were
separated by treating the sponge with hydrochloric acid. The
acicular spicules lost 13-18 per cent. of weight on heating to red-
ness for ten minutes in a platinum crucible. Before the blow-
pipe they were whitened, or became slightly ochreous in colour,
without a trace of fusion. Stellate spicules of five rays lost 12-86 per
cent. on calcination. The specific gravity, obtained by flotation in a
solution of iodides, was 2°032. But the spicules have a delicate tube
along the centre generally less than ‘001 mm. in diameter; and
allowing for this, the author obtained by calculation, 2-0361 as the
true specific gravity—which is that of opal.
The spicules are easily attacked by different chemical agents, so
that they ought to be very readily dissolved in sea-water on the death
of the animal. They were analysed after. calcination by Boricky’s
process, by means of pure hydrofluoric acid, after first boiling in
nitric acid and calcining, and they were proved to be pure silica.
When not previously calcined, but simply washed, the process yielded
a residue of hydrofluosilicate of soda in hexagonal prismatic crystals,
the origin of which it is hard to explain unless it be that the minute
tube of the spicules contains sea-water.
Fresh-water Sponges and the Pollution of River-water.{—E.
Potts has examined the sponges found in the forebay of the Phila-
delphia waterworks when the water was withdrawn, and considers
that the sarcode of fresh-water sponges does not slough off at the
approach of winter, so that these organisms do not ordinarily pollute
* Bull. Soc. Mineral. France, April 1884. Cf. Amer. Journ. Sci., xxviii.
(1884) p. 76.
t Proc. Acad. Nat. Sci, Philad., 1884, pp. 28-80.
758 SUMMARY OF CURRENT RESEARCHES RELATING TO
the water unless torn to pieces by violent freshets. He believes that
the whole of the sarcode retires into the statoblasts, from which it
issues again in spring.
Protozoa.
New Infusoria.—Dr. A. C. Stokes describes * a new genus and
six new species of fresh-water Infusoria.
Hymenostoma n. gen., H. hymenophora resembling Lembadion.
Trachelophyllum vestitum with needle-shaped objects scattered through-
out its substance which may be trichocysts, but their form and the
action of the light suggest that they may be crystals. They closely
resemble the acicular raphides of Lemna and other plants. T. tachy-
blastum, the specific name of which (“sprouting quickly”) was
suggested by the rapidity with which the animal repaired an injury
it sustained by a collision with an Oxytricha. Litonotus pleurosigma
resembling L. fasciola but differing from it and all other species of
the genus in the multiple contractile vesicles. LL. helus and Petalo-
monas disomata.
A new species of Vorticella (V. Lockwoodit) is also described + by
the same writer. The characteristics by which it may be dis-
tinguished from all Vorticelle are the existence and structure of the
cuticular prominences and the undoubted presence of two contractile
vesicles.
J. P. McMurrich describes { Metopus striatus which he considers
to be sufficiently distinguishable from the other species (M. sigmoides)
to justify its being treated as a distinct species.
J. G. Grenfell records § four new Infusoria from Bristol; Zootham-
nium Kentii differing from Z. dichotomum and all other species of the
genus in the characteristic covering of flocculent matter; Pyxicola
annulata || very like P. Carteri, but differing in dimensions and
undulations ; Platycola bicolor, so named ‘from the two colours of
the lorica” (lorica dark yellow, with a colourless neck)—it has a
very delicate membranous hood which has a large oval opening, is
retractile, and projects backwards from the top of the ciliary disk
covering the opening; P. aurita (n. sp. ?).
C. L. Herrick describes { Ophridium problematicum and an infu-
sorian closely related to Paramecium, but differing in several inter-
esting particulars from it and its allies. In form this animal is _
linear lanceolate (about 0:2 mm. long), tapering posteriorly to an
almost acuminate point. Anteriorly is a long vibratile proboscis, or
flagellum, which exceeds, when extended, the whole length of the
body. The mouth is situated at the base of this proboscis, and opens
into a very short infundibulum. The whole surface of the body and
proboscis is covered with minute cilia, which are inserted in rows,
* Amer. Mon. Mier. Journ., v. (1884) pp. 121-5 (9 figs.).
+ Amer. Natural., xviii. (1884) pp. 829-30 (2 figs.).
{ Ibid., pp. 830-2 (1 fig.).
§ Journ. of Micr., ili. (1884) pp. 133-8 (1 pl.).
|| But see Dr. Leidy, this Journal, iii. (1883) p. 77.
4 Science, iv. (1884) p. 73.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 759
giving the body a punctate appearance. Longer cilia surround the
mouth. The sarcode is transparent, and, apart from a few greenish
food-balls, contained only a large number (over a dozen) of oval
bodies of a similar character (endoplastules in an unobserved coiled
endoplast?). The motions of the animal are very quick, and are
occasioned chiefly by the whip-like motions of the proboscis, which
is extremely vigorous in movement, and alters its form greatly.
Apart from this rapid motion, it can propel itself slowly by means
of the cilia covering the entire surface. It is the type of a new
genus, and is named Phragelliorhynchus nasutus.
Parasitic Peridinian.*—G. Pouchet has met with a Peridinian
which in its early stage is parasitic on Appendicularie, These
parasites are pear-shaped, about 170 to 180 w long, with a nucleus
large in proportion. In colour they are a deep brown; they are
enveloped in a thin cuticle which they keep on becoming free, whilst
they abandon their pedicel. These detached individuals float in great
abundance on the surface of the sea and there undergo free or
independent segmentation, subdividing after the manner of a fecundated
vitellus into uninucleated spheres dwindling in size and growing
paler in colour as the process continues; but the products of this
segmentation always remain independent. A very thin cuticle is
thrown off as they divide. The spheres finally resulting, measuring
no more than 10-13 p, develope a long flagellum and a crown ef cilia,
and become minute Peridinians allied to Pulvisculus of Ehrenberg
Gymnodinium pulvisculus of Bergh). The whole process occupies
about 24 hours.
Observations on Flagellata.j—F. Blochmann commences with
some notes on Trichomonas vaginalis, at the anterior end of which
there are three flagella, from the base of which an undulating mem-
brane extends to about the middle of the body ; this membrane, never
hitherto observed, may be best seen if the creature is allowed to die
gradually. The T. batrachorum of Perty (the Cimenomonas batrachorum
of Grassi) is next considered, and here also an undulating membrane
was detected. If the monad is allowed to remain for some time under
the pressure of the cover-glass the whole margin of the animal is
seen to exhibit an active undulatory movement, though, of course,
this is not so regular as that of the membrane. A similar phenomenon
is to be observed in Trichomastix lacerte, a species lately detected by
Biitschli in the cloaca of Lacerta agilis; it has four flagella, one of
which is half as long again as the animal and is directed backwards.
Ozyrrhis marina is the last form described; within their bodies a
large number of fat-drops, often of considerable size, are to be
detected ; they take in solid nutriment. The author was able to
observe their multiplication by a mode of transverse division.
Geometry of Radiolaria.t—Prof. E. Hickel points out that the
four orders of the Radiolaria are distinguished by their geometric
* Comptes Rendus, xeviii. (1884) pp. 1345-6.
+ Zeitschr. f. Wiss. Zool., xl. (1884) pp. 42-9 (1 pl.).
t SB. Jenaisch. Gesell. f. Med, u. Naturwiss., 1883 (1884) pp. 104-8.
760 SUMMARY OF CURRENT RESEARCHES RELATING TO
form; in the Acantharia we have the quadrate octohedron, where
twenty radial spines are arranged in five sets of four spines each,
which are set quite regularly in meridional planes. In the Nassellaria
or Monopylee there is at first a monaxial form, which is in many
cases rendered bilaterally symmetrical; this is true also of the
Pheedoria or Tripylee. Stereoscopic forms are seen in the Spumel-
laria.
The Spheroida, which may be regarded as the stem-form of all
Radiolaria, ordinarily retain the spherical form of the central capsule,
and frequently give rise to the endospheric polyhedron; from these,
more complex forms arise by the development of spines along certain
rays. The Prunoidea are at first monaxial ellipsoids, and they finally
produce the much more complex Zygartide. The Discoidea arise
from the Spheroida by the shortening of the vertical primary axis,
and they at first have the form of biconvex lenses. The Larcoidea
begin with simple ellipsoid shells, and become complicated by the
development of further systems of network.
Polythalamian from a Saline Pond.*—E. v. Daday describes
a new genus—Hnizia—of Polythalamians from saline waters, which
have been studied by Prof. Entz, who finds that the infusoria living
therein are new forms, or have as yet been found in the sea only, or
are common to both fresh and sea water, while a fourth of the whole
number are only ‘known as fresh-water forms. The new genus is
characterized by having a multicamerate imperforate shell, which
contains a large number of siliceous plates ; the chambers are coiled
from left to right, and are only completely visible from the convex
side; at the outer partition of the terminal chamber there are larger
orifices, which are oval and tubular, and two smaller which are, vircular.
Tetrastomella is proposed as the specific name. Pa“
In the form of its shell Entzia resembles Rotalia, and belongs
to the group of the Helicostegia; the largest of the 16-chambered
individuals measured 0°42 mm., while the smallest 6-chambered
shell measured only 0°08 mm. As in Rotalia, the partitions
between the chambers were formed of two lamellw, one belonging
to the chamber in front and the other to that behind, but there
is not here any interseptal space; in all, as in the last partition,
there are two large and two smaller holes. As the siliceous
plates are completely imbedded in the substance of the shell,
the surface of the latter is, notwithstanding their presence, quite
smooth; they cannot, therefore, be regarded as foreign bodies, but
must be supposed to have been formed by the protoplasm. On the
whole, an investigation into the characters of the shell shows that it
unites peculiarities which are separately characteristic of chitinous
and arenaceous Rhizopods, and the close allies of the form are to be
found not so much in Rotalia, which it resembles in appearance, as
in Difflugia and the arenaceous Mono-and Polythalamia. The author
sums up his views as to the systematic position of Knizia in the
* Zeitschr. f. Wiss. Zool., xl. (1884) pp. 465-80 (1 pl.). Cf. Gruber’s note,
this Journal, ante, p. 580, which should have followed the above.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 761
following terms: It is the only as yet known continental Poly-
thalamian, and in the form of its shell resembles that of the sub-family
Rotaline of the group Globigerinz ; in structure the shell resembles
that of Trochammina ; in the structure of its partitions it agrees with
the perforate Polythalamia’; in that of the orifices of these partitions
with the Lagenide; the chemical constitution is that of Diflugia,
Trochammina, and some of the Globigerina, and it closely con-
nects the last with the Lagenidew by means of Trochammina and the
Rotaline.
Nuclear Division in Actinospherium eichhornii.*—R. Hertwig
concludes from his observations on the resting nucleus that the
coloured constituents of the nucleus (chromatin or nuclein) are not
spongy bodies; all the nuclein is contained in nucleoli, which are
stained by reagents. A subject of greater difficulty is presented by
the parts which are formed in addition to the nucleoli within the
nucleus. These are (1) the granulation which becomes visible on
the addition of reagents; (2) the paranuclear pieces which in the
fresh condition are seen to have various forms; (3) the highly
refractive corpuscles; and (4) the nuclear membrane. The first
three appear to be referable to a common structure of colourless
substance, which may be called paranuclein or achromatin, and
which fills up the interspaces between the nucleolus and the nuclear
membrane, It may be regarded as due to special thickenings of the
achromatic network. The author is acquainted with essentially
similar phenomena, which have presented themselves in the nuclei
of insects, and of which he will give an account at a later period.
The mode of division of the nucleus, as seen in Actinospherium, is
intermediate in character between what is seen in plants and animals
on the one hand, and in Protozoa on the other; in the latter, which
approach most nearly the diagrammatic scheme, the biscuit-shaped
constriction of the nucleus is most apparent; internal differentiations
of the nuclear substance are either completely wanting, or are nearly
fibrillar. (An exception to this is seen in the paranuclei of the
Infusoria.) On the other hand, in plants and animals the biscuit-
shaped constriction is obscure, the limits of the nuclear substance
and protoplasm disappear, and there is a mixture of the two sub-
stances. The whole division of the nucleus appears, therefore, as a
complicated and extremely regular rearrangement of the nuclear
particles, which lead to the important differentiation of achromatic
nuclear filaments and of chromatic elements; the two substances are
so sharply separated that they might be taken for elements which
had nothing to do with one another.
In Actinospherium we have, as in the other Protozoa, those changes
in form which the whole nucleus undergoes during division; but as
to its internal structure there are many points in which the nucleus
resembles that of animal ova; anuclear plate is formed, which divides
into lateral plates that separate from one another and the parts of the
lateral plates give rise to achromatic filaments. Before the appear-
* Jenaisch. Zeitschr, f. Naturwiss., xvii. (1884) pp. 490-517 (2 pls.).
Ser, 2.—Vo. IV, 38 5
762 SUMMARY OF CURRENT RESEARCHES RELATING TO
ance of the nuclear plate there is a stage in which it resembles that of
the Infusoria; as in them, bands, which may be coloured for their
whole extent, reach from pole to pole. This would seem to show that
in Actinospherium the achromatic filaments contain particles of
chromatin throughout their whole extent, and the same is probably
true of the Infusoria.
Tn addition to the interest which surrounds the nucleus of Actino-
spherium in consequence of its intermediate position, the mode of
formation of the lateral plates is also of interest. The view of
Flemming that in animal cells these plates are primitively laid down
separately does not apply to Actinospherium, where the first rudiment
of the nuclear plate is a single row of granules. The nucleus is also
distinguished by the possession of polar plates, or aggregations of homo-
geneous substance which are interpolated between the striated part
of the nucleus and the homogeneous protoplasmic cones ; they appear
to be derivatives of the cell-nucleus, formed by the clearing up of
its peripheral parts. The nuclear filaments are distinguished from -
those of animal and vegetable cells by their finely granular condition ;
they appear to consist of paranuclein, together with minute remnants
of colourable nuclein.
Parasite of the Wall of the Intestine of the Horse.*—M. Flesch
gives an account of a parasite which he has proposed to call Globidiwm
leuckarti, and which was found particularly in the connective tissue of
the intestinal villi of the horse, where its presence may give rise to
subacute inflammation. It ordinarily has.a spherical or ellipsoid
body sharply marked off by its capsule; in most cases its wall is
hollowed by a special fusiform or semilunar cavity, which is com-
pletely filled by a granular body or, as the author calls it, the
accessory body. In position it resembles the remains of the yolk in
the ova of Tenia. In another form the refractive spherules in the
interior of the parasite were solely parietal in position, and the
central space was occupied by a protoplasmic mass, which was very
uniformly granular. The author describes the stages in development
that he was able to observe, and then addresses himself to the question
as to whether he had here to do with a phase in the alternation of
generations of a higher organism, or whether the parasite was a
Sporozoon. He next gives a list of the known parasites of the horse,
which, as being fuller than that of Linstow, may be of use for other
purposes, and discusses the probabilities of his new form being a stage
in the life-history of any one of these ; this view being rejected he
addresses himself to the Sporozoon-view, against which it seems there
is nothing to be said, but in favour of which there is almost as little;
in fact it is, at present, impossible to assign a definite position to the
parasite. The relatively large capsules, and their position in the con-
nective tissue are against its being a Sporozoon; the part played by
the accessory body is unknown, and the evidence as to its being ex-
pelled from the organism is incomplete. The author hopes to be able to
make further and more complete investigations and meanwhile proposes
* Recueil Zool. Suisse, i. (1884) pp. 459-89 (1 pl.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 763
to speak of this obscure and abnormal parasite by the name he
originally suggested of Globidiwm leuckarti.
Sutherlandshire ‘‘ Eozoon.’’*—Prof. M. F. Heddle, after a careful
examination of the Eozoon-like structure that occurs in the marbles of
Assynt, recalls his previously expressed opinion as to its non-mineral
character and attributes to it a purely inorganic origin. The greater
part of this structure is formed of dark serpentine with some mag-
netite, whilst in the calcareous layers are imbedded fibres apparently
of wollastonite. Prof. Heddle states in a footnote that having un-
ravelled the Scottish Eozoon, he entered upon an inquiry into the
Canadian, in which he finds nothing he did not see in the Scotch
Specimens; at the same time the specimens examined were possibly
not good examples.
BOTANY.
A. GENERAL, including Embryology and Histology of the
Phanerogaimia.
Continuity of Protoplasm.}—P. Terletzki has investigated this
question with a view of determining what organs and what tissues in
the same plant display the phenomenon. For this purpose he has
taken in the first place Pteris aquilina, and has found a distinct
protoplasmic connection, in the rhizome, between the parenchymatous
cells, the conducting cells, and the sieve-cells, in each case among
one another, and between the sieve-cells and the conducting cells. |
On the other hand, he could detect no connection in the following
cases :—between the cortical cells among one another, between the
cortical and parenchymatous cells, the cells of the supporting bundles
among one another, the supporting bundles and the parenchyma, the
cells of the protecting sheath among one another, the protecting
sheath and the parenchyma, the protecting sheath and the conducting
cells, the bast-cells among one another, the bast-cells and the con-
ducting cells, the bast-cells and the sieve-cells, the conducting cells
and the scalariform vessels, the conducting cells and the tracheids
(annular or spiral conducting cells). These remarks apply to the
mature condition of the plant, and it is possible that in the cambial
condition the protoplasm of the whole of the cells may be in
connection.
The general facts were the same in other organs of P. aquilina,
and in other ferns.
Protoplasm was found in the intercellular spaces, especially in
the parenchyma of the rhizome, also in the parenchyma of the leaf-
stalk ; and this intercellular protoplasm was in connection with the
cellular protoplasm.
* Mineral. Mag., v. (1884) pp. 271-324 (11 figs.).
+ Ber. Deutsch. Bot. Gesell, ii. (1884) pp. 169-71.
3 Er 2
764 SUMMARY OF CURRENT RESEARCHES RELATING TO
Continuity of Protoplasm.*—G. Schaarschmidt believes that all
vegetable cells inclosed in a cell-wall and combined into a tissue
are placed in uninterrupted connection by means of threads of
protoplasm. aus
With regard to the occurrence of protoplasm in intercellular
spaces, he finds intercellular masses of protoplasm in Liriodendron
tulipiferum, also in the bud-scales of Aisculus Hippocastanum, in
Solanum Pseudocapsicum, Viscum album, &c. They occur especially
where the cells themselves contain no great quantity of protoplasm,
and can convert themselves into true cells by becoming invested with
a cell-wall; secondary intercellular spaces are then formed between
these and the older cells. This intercellular protoplasm the author
believes to be derived from the threads which pass from cell to cell.
Osmotic Power of Living Protoplasm.;—By an ingeniously
contrived apparatus M. Westermaier claims to have proved that the
pressure of the parenchymatous cells of the root-system, and the
osmotic suction of the protoplasm in the parenchyma of the stem,
acting together, are capable of raising a column of water to any given
height from the soil.
Structure of Pollen-grains.t—J. Vesque points out that the
pores in the pollen-grains are so arranged that, no matter in what
position the grains fall on the stigma, one at least of the pores is
ordinarily in contact with the moist membrane of the stigmatic
apille. The larger the grain the greater the number of pores (or
of folds), and their number, therefore, cannot be considered of great
taxonomic value. M. Vesque has found pollen-grains of Hieracium
having three to four pores, and that in the same anther.
The disposition of the external ornamentation of the pollen-grain
does not appear to depend on its mode of development, but on a
fixed geometrical law—that of phyllotaxy. Thus the complex pollen-
grain of the Chicoracesw, were it completely spherical, would be a
pentagonal dodecahedron; but as it is slightly ellipsoid, hexagonal
network is combined with the pentagonal. In the simplest case, that
which obtains in Scolymus, three hexagonal faces furnished with pores
are seen on the equator of the grain, the twelve remaining faces being
pentagonal, It is evident that the number of hexagonal faces in-
creases the more the grain approaches the cylindrical form. Thus
in Sonchus, Helminthia, and Lactuca it has twenty-one faces, three
hexagonal ones with pores, six without, and twelve pentagonal ones.
Seeds of Abrus precatorius.§—W. Tichomiroff classifies the
seeds of Papilionaceze hitherto examined into three classes, according
to the nature of their reserve material, viz.:—(1) Seeds containing a
fatty oil, starch, glucose, and aleurone, such as Arachis hypogea and
Dipteria odorata ; (2) those containing starch and aleurone only, as
paaee!: Noy. Lapok, viii. (1884) pp. 17-20. See Bot. Centralbl., xviii. (1884)
p. 162.
+ Ber. Deutsch. Bot. Gesell., i. (1883) pp. 371-83.
{ Comptes Rendus, xevi. (1883) pp. 1684-6.
§ SB. Vers. Russ. Naturf. u. Aerzte, Aug. 25, 1883. See Bot. Centralbl.,
XViii. (1884) p. 189.
ZOOLOGY AND BOTANY, MIOROSCOPY, ETO. 765
Pisum sativum, Phaseolus multiflorus, and Physostigma venenosum ;
(3) those containing coarsely granular aleurone and a fatty oil, as
Inpinus mutabilis and Trigonella Fonum grecum. Those of Abrus
precatorius constitute a distinct type; they contain a fatty oil and
albuminoids in the form of finely granular protoplasm, but neither
aleurone nor starch. Another characteristic is the persistence of the
nucleus and nucleoli in the peripheral parenchymatous layers of the
cotyledons. The crystals sometimes found in the parenchymatous
cells destitute of nucleus may consist of stearic acid or hesperidin.
The cell-wall is thickened in a porous manner, is not doubly refrac-
tive, and consists of pure cellulose. The testa is composed of four
layers, viz. :—(1) rods, colourless in the red part of the seed, while
in the black spot they are of a purple-violet colour; (2) palisade-
cells, distinguished by their length, their branching, and by the
folding and small diameter of their lower end; (3) parenchyma, com-
posed of cells elongated in the tangential direction ; (4) albumen, the
cellular nature of which is clearly defined in the first layers, while
the cells at a greater distance lose their individuality by becoming
flattened radially, and at length coalesce into a homogeneous pellicle,
which cannot be decomposed into its separate cells even by macera-
tion in chromic acid. In caustic potash this pellicle swells up
- strongly, and forms local projections. The hilum has two of the
layers of rods, but no palisade-cells, these being replaced by scleren-
chyma. With the exception of the albuminous layers the cell-walls
display distinct cellulose-reaction. By chloride of iron the presence
of tannins can be recognized in the albuminous layers and rods.
Comparative Anatomy of Cotyledons and Endosperm.*—J. God-
frin states, as a general result of a comparison of the structure of the
embryo and the endosperm, that those embryos the cotyledons of
which contain starch, whether alone or together with aleurone, are
never accompanied by endosperm. Those, however, which contain no
aleurone, even when thick (as Amygdalus, Armeniaca, Prunus, Corylus,
Juglans, Carya, &c.), may contain an endosperm, which is however
always very small. Embryos with thin or foliaceous cotyledons, are
not necessarily accompanied by endosperm, as witness Hedysarum
sibiricum, Casuarina quadrivalvis, Grevillea robusta, Hakea saligna, and
Acer.
The author classifies cotyledons under two heads: thick or tuber-
cular, and thin or foliaceous. The former, when mature, have a
simple epidermis without stomata or hairs, and in the interior a thick
parenchyma with large globular cells, between which are a number of
air-cavities. On germination very little modification of the tissues
takes place. Foliaceous cotyledons have, when mature, a simple
epidermis, often provided with stomata more or less developed; the
parenchyma is much smaller in mass, but is always divided into two
distinct layers. They vary greatly in their mode of development
during germination. In those which contain aleurone its absorption
is the first indication of germination.
* Bull. Soc. Bot, France, xxxi. (1884) pp. 44-51.
766 SUMMARY OF OURRENT RESEAROHES RELATING TO
Underground Germination of Isopyrum thalictroides.*—This
species presents one of the few examples of underground germination
among flowering plants. A. Winkler has examined the process in its
various stages, and points out that it exhibits a difference from the
similar phenomenon in Anemone nemorosa and ranunculoides belong-
ing to the same natural order. While in Anemone the unstalked
cotyledons project from the testa of the seed, and, as in typical
dicotyledons germinating above the surface of the soil, are opposite to
cne another, in Isopyrum they remain inclosed within the testa, and
are placed on tolerably long stalks.
Stomata of Pandanacee.t{—R. F. Solla has closely studied the
stomata in the leaves of a large number of species of Pandanus, and
distinguishes three types:—(1) the simplest and most common form,
represented by Pandanus tnermis, in which the cells contributing to
its formation are only two in number; (2) the type of P. graminifolius,
which occurs only in a few Pandanacee ; the auxiliary cells, eight in
number, are all thickened, their apices thus forming a protuberance
which rises above the level of the epidermal cells, the walls of the
latter being also thickened; (8) the type of P. utilis, resembling the
stomata of Aloe and other allied plants ; the thickening here extends
from the auxiliary cells to the epidermal cells to such an extent as to
form little lumps on the surface, completely concealing the outline
of the stoma. A number of measurements are given of the size of
the stomata in different species, and of the relative number found on
a unit of superficies.
Changes in the Gland-cells of Dionea muscipula during
Secretion.j—According to W. Gardiner there are four periods in the
process of digestion by the leaves of the Venus’s fly-trap, viz. the
resting, the secreting, the absorbing, and the period of recovery.
In the resting stage the gland-cells exhibit the following structure :
—In each cell the protoplasm is closely applied to the cell-wall,
leaving a large central vacuole, which is filled with the usual pink
cell-sap. The protoplasm is very granular, especially round the
nucleus, which is situated at the base of the cell, and is large and
well defined. At the end of the secreting period, which appears to
be about twenty-four hours after stimulation, movements of the pro-
toplasm have taken place, in consequence of which the nucleus now
occupies the centre of the cell; numerous strands of protoplasm
radiate from the nucleus to the parietal protoplasm, dividing the
vacuole into several smaller ones. The protoplasm is now nearly
homogeneous, clear and hyaline, and the nucleus has become much
smaller. In the ordinary leaf-tissue special cell-contents make their
appearance after the absorption of the food. About thirty-six hours
after feeding the cells contain a large number of tufts of crystals in
the vacuole, which adhere to the inner surface of the protoplasm.
They consist of fine acicular crystals, which crystallize out with
great regularity, and radiate from a central point. They are of a
* Flora, Ixvii. (1884) pp. 195-8 (1 pl.).
+ Nuov. Giorn. Bot. Ital., xvi. (1884) pp. 171-82 (2 pls.).
{ Proc. Roy. Soc., xxxvi. (1884) pp. 180-1.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 767
yellow-green colour, insoluble in alcohol, in 1 per cent. acetic acid,
and in 1 per cent. hydrochloric acid, soluble with difficulty in 5 per
cent. solution of potash. After forty-eight hours the cell-contents
are of a different nature. The cells now contain numerous bodies
which present the appearance of flat spherocrystals. They are
usually perfectly circular in outline, and are clear and colourless,
insoluble in alcohol, but extremely soluble in water.
In Drosera similar changes take place, but much more rapidly.
Septal Glands of Monocotyledons.*—P. Grassmann describes the
nectar-glands found in the septa of the ovary, which are peculiar to
Monocotyledons, and in them occur only in the series of Liliiflore
and Scitamines. They occur one in each septum, and therefore
almost invariably three in each ovary. The gland forms in the
septum a fissure of varying size and form, visible even to the naked
eye. It usually occupies the greater part of the septum, and is bounded
on each side by a secreting layer, consisting of from two to three rows
of cells. In the same family they are very constant in form and
size. The glands are filled with nectar, which escapes by means of a
narrow canal to the receptacle, the mode of escape varying according
as the ovary is superior, half-inferior, or inferior.
The glands are formed by the incomplete cohesion of the carpels
in the septa; they are recognizable at a very early stage of develop-
ment, and are then quite destitute of nectar, and the stages of cohesion
can be very readily followed. Their object is unquestionably the
attraction of insects to assist in fertilization. They are found only in
species with conspicuous flowers; the nectar always contains grape
sugar, and, when it flows out of the glands, either collects on the
receptacle or unites with the juice flowing from nectaries in other
parts of the flower. It begins with the opening of the flower, and
usually lasts several days. ‘The canal is also surrounded by secreting
cells which pour out nectar.
Secretory System of Composite.t—According to P. Van Tieghem,
the secretory system of Composite presents itself in three different
forms—as oleiferous canals, as anastomosing laticiferous cells, and as
long, isolated resiniferous cells. Disregarding some transitional
forms, the first of these types is characteristic of the Radiiflore, the
second of the Liguliflore, and the first and third of the Tubuliflore.
The present paper is devoted especially to the situation and structure
of the laticiferous network of the Liguliflore, which he finds to be
situated in the layer of cells previously denominated by him the
pericycle, situated between the endoderm and the first sieve-tubes of
the fibrovascular bundles of the central cylinder. This network does
not belong to the liber, being separated from the sieve-tubes which
constitute the outermost portion of it by the entire thickness of the
sclerenchymatous bundle. From here it may extend right and left,
and may even penetrate between the liber and the sclerenchyma, the
* Flora, Ixvii. (1884) pp. 113-28, 129-36 (2 pls.).
+ Bull. Soc. Bot. France, xxx. (1884) pp. 310-3.
768 SUMMARY OF CURRENT RESEARCHES RELATING TO
internal cells of the pericycle remaining for a time in a merismatic
condition, and then becoming differentiated here and there into
laticiferous cells.
The isolated resinous cells of the Tubulifloree, which contain a
laticiferous and resiniferous secretion, occupy precisely the same
position, differing from them only in their form and in their mutual
relations.
Chemical Constituents of Plants.*— M. Ballo is of opinion that
oxalic acid has a much more important function in vegetable physi-
ology than is generally supposed; the carbohydrates being formed
from the reduction of this and other vegetable acids rather than by
direct synthesis from carbonic acid and water. Tartaric acid, on the
other hand, is a product either of the oxidation of carbohydrates or
of the reduction of oxalic acid, as is also the glycolic acid which
occurs in unripe grapes and in the leaves of the wildvine. As regards
all other products of oxidation, the less the amount of oxidation, the
more complicated is the product and the more nearly related to the
original substance; while, when oxidation is carried on further, we
get the original substances by which the plant is nourished. The
vegetable acids are the most common products of oxidation in the
plant. A portion of the oxalic acid is used in the decomposition of
calcium sulphate, the rest as the raw material for the production of
glycolic, tartaric, malic, succinic, and other acids.
If formic acid is heated with nitric acid, it is oxidized into
carbonic acid and water, the nitric acid being reduced to nitrous
oxide ; but at the commencement of the process oxalic acid is formed ;
and the author believes that this process takes place in nature,
according to the equation :—
2 H, CO, + O = H, ©, O, + H, O;
and that this is one of the reasons why nitrates are so valuable to the
growing plant. In the living plant a portion of the nitrates is used
in the production of ammonia and other substances nearly related to
it, and another in the conversion of amide-compounds into alcohol-
compounds. The greater part is reduced to the state of nitrous oxide ;
and from this nitric acid is again formed through the agency of
oxygen and water. Hence a small quantity of nitrates can bring
about the formation of a large quantity of oxalates.
Electric currents exist without doubt in the living plant, and it is
possible that in some cases these may be converted into chemical
work consisting in the decomposition not merely of water but also of
salts. The products of decomposition of these salts may cause the
formation of metal-derivatives at the negative pole, of derivatives with
negative radicals at the positive pole. Hlsewhere these substances
may again combine with one another, and the same process be then
again repeated. Hence the comparatively small quantity of inorganic
salts found in plants.
* Ber. Deutsch. Chem. Gesell., xvii. (1884) p. 6. See Naturforscher, xvii.
(1884) p. 123.
ZOOLOGY AND BOTANY, MIOROSCOPY, ETO. 769
Structure of Leaves.*—E. Mer has studied the cause of the
different forms of cells in terrestrial and in aquatic leaves. The
structure of a leaf with a well-developed blade and petiole, in which
the normal position of the former is horizontal, is due to its situation.
The upper face receives a large amount of light, and is in conse-
quence well nourished, and the cells of the upper parenchyma acquire
a great increase in length, or become palisade-cells. The epidermal
cells of the upper surface, well nourished in consequence of their
vicinity to the assimilating parenchyma, increase actively and regu-
larly, and acquire polyhedral forms, with thick walls and a still
thicker cuticle; the active development of which they are the seat
prevents the accumulation in them of food-materials and the forma-
tion of stomata. The parenchyma of the lower surface receives less
light and is in consequence less well nourished. Its cells grow
transversely, and finally separate, leaving between them larger or
smaller lacunz; their walls sometimes become slightly wavy. The
cells of the hypodermal layer of the lower surface do not increase in
length transversely nearly so much as those of the upper surface,
and even become rounded.
The hairs originate in the bud, and chiefly on the lines of maximum
nourishment, the veins. The stomata always make their appearance
at the end of the hyponastic or commencement of the epinastic
period, during that phase of development included between the com-
mencement of the increase in length of the palisade-cells, and the
appearance of the waviness in the epidermal cells of the lower surface.
In the submerged leaves of aquatic plants the sinuosity of the
walls of the epidermal cells is due to insufficiency of nutriment.
Transparent Dots in Leaves.j—P. Blenk has made an ex-
haustive examination of the transparent dots in the leaves of a very
large number of plants belonging to a great variety of natural orders,
from the point of view of their structure and mode of development,
and especially of their value in classification. He considers that too
little account has hitherto been taken of their presence or absence by
systematists, the anatomical structure which results in the formation
of these dots being often a point of great importance, which may even
be made use of in dried specimens. For example, cells with mucila-
ginous cell-wall in the interior of the leaf occur only in Anonace»
and Laurinex, and may possibly indicate a close relationship between
these orders.
The various causes of transparent dots or lines in leaves are the
following :—Secreting cells, round intercellular secreting spaces of
either lysigenous or schizogenous origin, secreting passages, epider-
mal or parenchymatous cells with mucilaginous cell-walls, cells con-
taining mucilage, raphides-cells, cells with single crystals or clusters
of crystals, cystoliths, spicular cells, branched sclerenchymatous
bundles, groups of sclerenchymatous cells, depressed pits with or
* Bull. Soc. Bot. France, xxx. (1883) pp. 110-30.
t Flora, Ixvii. (1884) pp. 49-57, 97-112, 136-14, 204-10, 223-5, 275-83,
291-9, 389-49, 355-70, 371-86.
770 SUMMARY OF CURRENT RESEARCHES RELATING TO
without hairs, crevices in the tissue, stomata. The secreting cells,
spaces, or passages may contain resin, gum-resin, balsam, or an
essential oil.
Secreting cells are an extremely common cause of transparent
dots, and are usually characteristic of whole families or at least of
genera. Round intercellular secreting spaces may be lysigenous, as
in Rutacez, or schizogenous, as in Hypericinee, the two kinds show-
ing no difference in the mature condition. Both kinds are of great
importance from a systematic point of view, furnishing distinguishing
characters for entire families. Thus lysigenous secreting spaces
occur in the Rutacew, Myoporinee, and Leguminose ; schizogenous
are constant in the Hypericineze, Myrsineze, Samydex, and Myrtacee.
Intercellular secreting passages of schizogenous origin cause trans-
parent lines in a number of Guttifers, and in some species of
Hypericum.
Epidermal cells in which the inner wall next the parenchyma of
the leaf is strongly thickened and mucilaginous cause pellucid dots in
a number of families and genera. Cells in the interior of the leaf
with all the cell-walls strongly mucilaginous occur in Anonaces and
Laurinez, but not in all the species. Cells with mucilage in the
interior are found in the Ampelidex, and especially in the American
species of Cissus.
Raphides-cells are of great importance systematically. They
are sometimes replaced by cells with single very long prismatic
crystals. Transparent dots caused by cystoliths occur in Ficus,
Momordica, and some Acanthacee.
Of sclerenchymatous elements the most common are spicular
cells. Round groups of sclerenchymatous cells also occur, and
elongated sclerenchymatous bundles ; but all these forms are of com-
paratively small value systematically. Stellately branched scleren-
chymatous bundles, the so-called ‘‘internal hairs,’ are constant in
Nymphea and in the genus Ternstremia.
The following are only occasional causes of transparent or pellucid
dots, of but little systematic importance :—Depressed pits in some,
Capparidez and in Victoria regia ; depressed glands in some Meliacee ;
rupture of the tissue in some Burseracese, in Nyssa capitata and
Placodiscus leptostachys ; cells with spherocrystalline deposits of
calcium sulphate, sodium oxalate, or of an organic substance of un-
known nature ; the meshes of the network of vascular bundles in some
Capparidez and Portulacex, and finally stomata.
Secretory System of the Root and Stem.*—In pursuance of
previous investigations P. Van Tieghem continues his examination of
the structure and position of the secretory system in the following
natural orders:—Umbellifere, Araliacee, Pittosporee, Composite,
Clusiaceze, Hypericaceze, Ternstroemiacee, Dipterocarpes, Liquidam-
bareze, and Simarubaces. In the Umbellifere and Araliacexe the
system, which occurs in the roots, tigellum, and cotyledons, is
nie ee Soc. Bot. France, xxxi. (1884) pp.” 29-32, 43-4, 112-6, 141-51,
ZOOLOGY AND BOTANY, MIOROSOOPY, ETO. 771
continued indefinitely from the cotyledons into the stem and leaves,
in the pericycle, more or less near to the liber of the vascular bundles,
but not in the liber itself. The same is also the case in the Pitto-
sporex. In the root of Ligulifloree (Composite) the laticiferous
network occupies the internal edge of the liber within the sieve-
tubes, while in the stem it is situated in the pericycle outside the
sieve-tubes. In those Tubuliflore which possess a secreting system,
its position in the roots is the same as in the Liguliflore. The root
of the Radiate and Liguliflore is altogether destitute both of a
laticiferous network and of isolated resiniferous cells, although
possessing an endodermic oleiferous system.
In the Clusiacew the only regions in which secreting canals are
not found are the pericycle, which forms in the stem a sclerenchy-
matous ring, and the primary or secondary xylem of the vascular
bundles. The Hypericaceze resemble the Clusiacea in the constant
presence of secreting canals and in their general disposition, but
differ from that order in their presence in the pericycle. The
Ternstreemiacee present in this respect a close resemblance to the
Clusiacee. The Dipterocarpex differ, not only from these orders,
but from all other angiosperms, in the presence of secreting canals in
the xylem. In the complicated arrangement of the vascular bundles
in the petiole they approach Malvacee.
Liquidambar and Altingia have their entire vegetative structure
traversed by a system of oleiferous canals belonging to the primary
liber in the roots, to the primary xylem in the stem and leaves. They
may be said to combine the root of Anacardiaces with the stem and
leaves of Dipterocarpew. The Simarubez have canals only in the stem
and leaves, not in the root. The Dipterocarpee, Liquidambaree,
and Simarubez have this in common, that the stem and leaves have
secreting canals localized in the primary xylem; they are dis-
tinguished from one another by the position of the canals in the
root; in the Dipterocarpex these are in the primary xylem, in the
Liquidambarexw in the primary liber; in the Simarube there are
none. In the only other order which has secreting canals in the
xylem, the Conifer, they occur only in the root and stem.
Anatomical Structure of the Root.*—J. Constantin points out the
great uniformity in the structure of the root as compared with that of
the stem in the great divisions of the vegetable kingdom; but this he
attributes to the much greater uniformity in the nature of the en-
vironment. In differing external circumstances he finds the structure
of the root to vary in precisely the same directions as that of the stem.
When a root is fully exposed to the action of light, the thickness .
of the bark is less than in an underground root, while the central
cylinder is, on the other hand, more developed. The endodermic
punctations, so clear in underground roots, become indistinct in roots
exposed to the light; all the fibrous tissues are more developed, both
in the central cylinder and in the bark; and lignification has advanced
considerably further.
* Bull. Soc. Bot, France, xxxi. (1884) pp. 25-8.
172 SUMMARY OF OURRENT RESEARCHES RELATING TO
In roots entirely submerged in water, there is a well-developed
intercellular system, while the vascular system is less developed.
When an aquatic plant is transported on to dry land, the intercellular
system diminishes, while the vessels become more numerous, and
lignification is carried on further.
Growth of Roots.*—R. v. Wetistein thus states the laws which
govern the growth of roots :—
1. In the first periods of development the growth is uniform ;
afterwards, from the period of germination, it is localized ; the position
of the zone of maximum growth varying. It begins at the collar,
advancing gradually towards the apex, where it ceases.
2. The nearer the growing region approaches the apex of the root,
the less rapidly does it advance.
3. The length of the growing region increases as it approaches the
apex of the root, attains 2 maximum, and then decreases.
4. Neither the nature of the environment nor variations in tem-
perature exercise any influence on the law of growth; even decapitation
may not essentially alter the course of growth, at least at first.
5. As long as the region of most vigorous growth has not ap-
proached within about 4 mm. of the apex, the growth of the young root
depends only on the elongation of the cells already formed in the seed.
The first stage of growth is the result of this elongation taking place
in fresh layers of cells, and the growing region thus advancing towards
the apex.
6. When the zone of maximum growth has advanced to within
4 mm., or less, of the apex, cell-division and elongation of cells
go on pari passu. In the second stage of growth the cells freshly
formed near the apex contribute to the growth of the root by their
elongation.
7. The first stage of the growth of roots is independent of the
conduction of reserve-materials from the cotyledons or endosperm.
8. “Sachs’s curvature” depends on a difference in the growth of
the two sides of the root. This fact is in harmony with Wiesner’s
explanation of the occurrence of spontaneous phenomena of nutation
in other organs.
Growth in length of decapitated and uninjured Roots.j —
H. Molisch confirms Wiesner’s statement that roots when deprived
of their growing point grow less in length than uninjured roots under
similar conditions of growth; and that this difference of growth in
length depends greatly on temperature, being inconsiderable when
the temperature is low. He further believes that the reasons why
Kirchner has come to a different conclusion are probably that he
worked at too low temperatures; that he removed too small a
quantity from the apex of the root; and that the number of ex-
periments performed was not large enough to arrive at definite
conclusions.
* Anzeig. K. Akad. Wiss. Wien, Feb. 14, 1884. See Bot. Centralbl., xvii.
(1884) p. 359.
+ Ber. Deutsch. Bot. Gesell., i. (1883) pp. 362-6.
raed
ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 173
Geotropism and Hydrotropism of Roots.*—A. Tomaschek main-
tains that the degree of geotropism in a root does not depend on the
rapidity of growth ; nor is it affected even by severe injuries, pro-
vided the apex of the root is left uninjured. He regards the view of
Darwin as fully established that the receptivity for the influence of
gravitation resides in the apex of the root only, and moreover that the
apex is susceptible to psychometric differences in the environment
(hydrotropism), and that this susceptibility is conveyed to the adjacent
parts.
Water-glands and Nectaries.;—W. Gardiner confirms Sachs’s
view that the exudation of water from water-glands is entirely due
to root-pressure, and never takes place with cut organs; although in
some cases (Fuchsia globosa) an abundant exudation from hairs in the
vicinity of the water-glands gives the appearance as if it proceeded
from the latter. Light retards very considerably the exudation of
water both from water-glands and from those secreting epidermal
structures which are not dependent on root-pressure. Water-glands
are, as a rule, much more fully developed in Dicotyledons than in
Monocotyledons, which may be due to the latter being of a more
generally aquatic habit. The chief function, both of water-glands
and of thin-walled epidermal cells placed in connection with a
vascular bundle, is to allow of the escape of superfluous water, which
would otherwise cause injection of the intercellular spaces, and even
rupture of the tissue.
Nectaries, i.e. structures of whatever morphological value de-
signed to secrete a saccharine fluid, do not, as Sachs has pointed out,
discharge their nectar in consequence of root-pressure, but from the
activity of the cells of the nectary themselves.
Folds of Cellulose in the Epidermis of Petals.t —E. Kéhne
describes a number of different ways in which the lateral cell-walls
of the epidermal cells of the petals are thickened and folded in a
variety of plants. He discusses the purpose of these foldings, and
believes it to be merely mechanical, in strengthening the epidermal
layer of cells.
Anatomical Structure of Cork-woods.s—A. Gehmacher gives a
detailed account of the anatomical structure of several extremely
light woods from the tropics known as “ cork-woods,” viz. Alstonia
scholaris from India, Bombax Buonopozense from Senegal, B. Ceiba,
B. pentandrum from India, Eriodendron anfractuosum from India,
Kerminiera Elaphroxylon from the White Nile, and the very beautiful
Chinese “ cork-wood,” which comes apparently from the root of a
Conifer. They all belong to the wood itself, and not to the bark.
“Filiform Apparatus” in Viscum album.||—W. Scrobischewsky
describes the “filiform apparatus” of the embryo-sac as very con-
* Oesterr. Bot. Zeitschr., xxxiv. (1884) pp. 55-9,
+ Proc. Camb. Phil. Soc., v. (1884) pp. 35-50 (2 pls.).
t Ber. Deutsch. Bot. Gesell., ii. (1884) pp. 24-9 (1 pl.).
§ Oesterr. Bot. Zeitschr., xxxiv. (1884) pp. 149-55.
| SB. Vers. Rus. Naturf. u. Aerzte, Odessa, Aug. 24, 1883, See Bot. Centralbl.,
xviii. (1884) p. 156.
774 SUMMARY OF CURRENT RESEARCHES RELATING TO
spicuous in the mistletoe. The division of the nucleus in the
embryo-sac takes place in the ordinary way. At each end of the
embryo-sac three cells are formed, three antipodals, two synergida,
and an oosphere. The seventh nucleus les within the protoplasm
near the oosphere, and is remarkable for its size and its elongated
form; this is the nucleus of the embryo-sac. At this period a small
vesicle is formed in the wall of the embryo-sac in close proximity to
the synergide, into which vesicle the two synergide project, destroy-
ing its wall at two spots; the cell-wall which is thus destroyed
assumes a mucilaginous character, in the form of very slender threads,
arranged in the form of a cone, and constituting the peculiar “ filiform
apparatus.” The synergide then also begin to exercise a destructive
effect on the outer part of the split wall of the embryo-sac; at two
points, corresponding to the apices of the synergide, openings
appear through which the pollen-tube can project free into the
interior of the sac. By careful pressure the “ filiform apparatus ”
can often be separated from the synergidew. The threads of the
latter coalesce, after fertilization, into long homogeneous semi-fluid
masses.
The function of the synergide is therefore to facilitate the access
of the pollen-tube to the oosphere (germinal vesicle) by absorption of
the wall of the embryo-sac. All stages in the division of the nucleus
can very easily be followed out in the formation of the endosperm of
Viscum album ; they agree with those described by Strasburger in the
case of Hyacinthus orientalis.
Action of Heat upon Vegetation.*—A short note upon this
subject by A. Barthélemy deals with (1) the action of heat upon the
development and direction of growth of roots, (2) the action of heat
upon the phenomena of heliotropism.
1. One experiment was made upon hyacinths growing in vessels
of water; it was found that they invariably grew towards a heated
brazier placed in their vicinity, whereas the leaves grew away from
the source of heat and towards the window which was brightly
illuminated. In another experiment a vessel of water was divided
by a glass partition into two compartments, one of which contained
hot water while in the other were placed hyacinth roots floating in
cold water; the roots always grew towards the glass plate, and
applied themselves closely to it. When the water was coloured by
means of lampblack it was found that the growth of the roots
towards the heated compartment was checked—possibly on account
of the increased conductivity causing the temperature round the roots
to become more uniform, or by the lessening of the diathermancy
of the water which would hinder the action of the heat upon the
roots.
2. The experiment made to show the action of heat upon helio-
tropism is described by the author as follows:—A pencil of solar
rays was made to fall either directly or by a mirror upon a Dipsacus
placed in a vase in a dark room ; the stalk rapidly bent towards the
* Comptes Rendus, xcviii. (1884) pp. 1006-7.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 775
source of light, but rapidly recovered as if by a rebound as soon as
the light was removed and the roots of the plant watered.
Relation of Heat to the Sexes of Flowers.* —T. Meehan
referring to his former communication f as to male flowers entering
on active growth at a much lower temperature than the female,
exhibited catkins and flowers of the European hazel (Corylus avellana),
which, for the first time in several years, had perfected themselves
contemporaneously. The past winter had been distinguished by a
uniform low temperature the entire season. In other years a few
warm days in winter would advance the male flowers so that they
would mature weeks before the female flowers opened: hence the
females were generally unfertilized, and there were few or no nuts.
Under this law, it was evident, amentaceous plants could not abound
to any great extent in countries or in localities favourable to bringing
forward the male flowers before there was steady warmth enough to
advance the female. He thought this was likely to be the reason
why so many coniferous trees under culture in the vicinity of
Philadelphia bore scarcely any fertile seed in their cones—a fact
which had often been remarked in connection especially with the
Norway spruce. The male flowers would mature before the female
had advanced far enough to be receptive of the pollen.
Influence of Light on the Structure of the Leaves of Allium
ursinum.t—C. Musset has investigated the truth of the statement
that light has an influence on the leaves of certain plants, and finds
that, in Allium ursinum, at any rate, there is no change in structure
which can be ascribed to the action of light.
. Effect of Light and Shade on Pine-leaves.s—E. Mer describes
at length the difference in the development of the “needles” of Abies
excelsa, according to their position on the tree or the branch, and
according to whether the tree stands alone or is closely surrounded
by others, depending therefore on the amount and the direction of the
light which falls on the leaves.
Movement of Water in Plants.|\—As a contribution towards our
knowledge of the causes of the movement of water in plants,
J. Dufour has made a series of observations of the relation between
the size of the cell-cavity and the thickness of the cell-walls in a
number of woody plants, with the following approximate results :—
Sambucus nigra, cell-cavities (without vessels) 16-18-8 per cent.,
walls of wood-cells, 81:2-84 per cent.; Fagus sylvatica, diameter of
- vessels 7°4, cell-cavities 7:5, xylem-parenchyma 17-0, cell-walls
68:1 per cent.; Hamatoxylon campechianum, cell-cavities 4.-8-23-0,
cell-walls 77-95°2 per cent.; Cosalpinia echinata, cell-cavities 4+ 2-
14-0, cell-walls 86-958 per cent.; Alnus incana, cell-cavities 43+ 5-
* Proc. Acad. Nat. Sci. Philad., 1884, pp. 116-7.
¢ See this Journal, iii. (1883) p. 532.
} Comptes Rendus, xcviii. (1884) pp. 1297-8.
§ en ng trees rig ote ae (1883) pp. 40-50.
|| Arbeit. Bot. Inst. Wiirzburg, iii. (1884) pp. 36-51 and Arch. Sci. Phys.
Nat., xi. (1884) p. 15. Cf. this Journal, ante, p. 414. eg
776 SUMMARY OF CURRENT RESEARCHES RELATING TO
51-6, cell-walls 45-8-56°5 per cent. ; Buxus sempervirens, cell-cavities
of wood-cells 7°9, cavities of vessels 9°8, walls of vessels and cells
82°83 per cent.; Morus alba, cell-cavities (without vessels) 10-6—25 ;
cell-walls 75-89:4 per cent.
The author retains his opinion that the cell-cavities and vessels of
wood are in no way necessary for the transport of the sap. This
movement takes place entirely in the cell-walls, in consequence of a
little-known property belonging to their internal nature. It is, no
doubt, to a certain extent influenced also by transpiration.
Movement of Water in the Wood.*—Both the prevalent theories
with regard to the causes of the ascent of the sap in woody plants—
that of imbibition, that it ascends through the porous walls of the
vessels, while the cell-cavities are filled with air, and that of gas-
pressure, that at the time of greatest transpiration the vessels are
filled partly with sap, partly with bubbles of rarefied air—depend on
the hypothesis that the cell-cavities or vessels of the wood contain air
under normal conditions. M. Scheit throws grave doubts on the
elementary fact on which both these theories are founded. The air-
bubbles constantly found in the vessels in microscopical sections have
probably entered in the process of dissection, and those said to have
been observed in sections under oil are certainly in some cases bubbles
of aqueous vapour. There are only two possible ways in which air
can reach the tracheids, through the stomata or through the root.
The first hypothesis is excluded by the fact that there is no direct
connection between the stomata or the intercellular spaces and the
vessels; the second is very improbable; it is difficult to understand
how air could pass through the fluid which permeates the parenchyma
and collect in bubbles. By a number of actual experiments on Abies
balsaminea and eaxcelsa, Taxus baccata, Acer platanoides, and Péeris
aquilina, Scheit also determined the impermeability to air of moist
wood and of the closing membrane of pits; the water-conducting
organs contain nothing but water either in the liquid or gaseous state.
The author believes that the passage of water from the parenchyma
into the tracheids is greatly facilitated by the bordered pits. The
water is absorbed from the soil by the youngest parts of the roots and
the root-hairs by means of osmose; the osmotic pressure is greatest
at the thinnest spots of the cell-wall, the pits; and, as far as the
elasticity of the closing membrane of the pits permits, this membrane
is pressed in towards the cavity of the adjoining vessel, and brought
into a position for filtration, so that water can now readily pass into
the vessel. The manometer indicates that this root pressure may
amount to as much as one atmosphere. The water thus pressed
into the empty vessels rises through capillarity, and the root pressure
has thenceforward nothing more to do than to place the closing
membrane of the pits in a position for filtration ; a continuous column
of water being thus formed in the plant. The whole plant is per-
meated by a system of capillary tubes having its lower end in a tissue
which absorbs water, the parenchyma of the root; its upper end in a
* Bot. Ztg., xlii, (1884) pp. 177-87, 193-202.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 777
tissue which gives off water, the spongy parenchyma of the leaf; in
the other parts of the plant this system is accompanied by the paren-
chyma of the wood and medullary rays, which latter convey to the
cortex the water required by it; while in the stem the whole conduct-
ing apparatus is also enveloped by cambium.
Measurement of Transpiration.*—Under the name Potetometer
J. W. Moll describes an instrument invented by him for the purpose
of exactly measuring the quantity of water given off, in any space of
time, by the foliage of plants.
Exhalation of Ozone by Flowering Plants.t—A series of ex-
periments conducted by Dr. J. M. Anders go far to prove that flower-
ing plants, especially odoriferous ones, give off ozone under the
influence of sunshine. Schénbein papers suspended in glass cases
with flowering plants showed under favourable conditions marked
blue shades, and though Dr. Anders does not wish to say dogmati-
cally that all the changes seen in the test-papers were produced by
ozone, he considers it incontestable that this substance was the chief
agent in their production.
With regard to the probable mode of its production, Dr. Anders
concludes that “during the formation of the seeds there is a rapid
metastasis of phosphorites, in the form of phosphoric acid, and the
phosphates to that organ of the plant, and it may be reasonably
supposed that in the chemico-vital changes going on in the ovules,
phosphorus is liberated and acted upon by the moisture which the
leaves and petals are so actively transpiring.” Under these circum-
stances it not improbably follows that those flowers which produce
the most seed are the largest generators of ozone, so that the sunflower
may have other than esthetic claims to our admiration.
Acids in the Cell-Sap.t—G. Kraus has examined the relative
proportion of acid in different plants, in different parts of the same
plant, and in the same part at different times of the day. As a rule,
in most woody and herbaceous plants, the leaves contain the largest,
the root the smallest quantity of free acid, though there are exceptions
to the rule. In the stem the acidity increases from above downwards,
or, in other words, increases absolutely with age. He regards the
acids as not mere products of excretion in metastasis, but as playing
an important part in the processes of life. In geotropic curvatures
the amount of free acid is both relatively and absolutely less on
the convex side.
The formation of acid is, as a general rule, hindered by light.
As regards periodicity, the maximum of free acid is found in the
early morning; the amount then decreases steadily till the evening,
when it reaches its minimum, increasing again gradually during the
night.
* Arch. Néerl. Sci. Exact. et Nat., xviii. (1883) pp. 469-78 (1 pl.).
+ Amer. Natural., xviii. (1884) pp. 337-44, 470-7, Of. Engl. Mech., xxxix,
(1884) pp. 313-4.
$ Abh. Naturf. Gesell. Halle, xvi. (1884), See Bot. Centralbl., xviii. (1884)
p- 100.
Ser, 2.—Vou. LV. 3 RK
778 SUMMARY OF CURRENT RESEARCHES RELATING TO
The most abundant acid in the sap is malic, occurring either free
or as calcium malate; the amount of this salt appears to remain
nearly constant by day and by night.
Kraus regards the vegetable acids as secondary products of
respiration, occurring especially in those parts which contain abund-
ance of protoplasm, the medium of respiration. He does not support
the view that they are products of assimilation.
New Colouring Substance from Chlorophyll.*—R. Sachsse dis-
tinguishes two varieties of the derivative from chlorophyl] previously
described by him as phyllocyanin, but which he now prefers to call
pheochlorophyll, viz.:—a phzochlorophyll, almost insoluble, and
B pheochlorophyll, soluble with difficulty in alcohol. The latter
substance is, when dry, nearly black, insoluble in water, soluble in
alcohol, from which it separates on cooling in amorphous flakes,
and in benzol. It is distinguished by its peculiar brown-yellow-
green colour, and its formula is C,;H,,N,0,.
By heating 8 pheochlorophyll with baryta water or fusing with
soda, it is deprived of carbonic acid, and a new substance obtained
with the composition C,;H,;N,0,, which, when dry, is of a dark red-
brown colour. Its solution in alcohol is dark red, which a few
drops of sulphuric acid change to light red-violet. The colour itself
and the spectrum are very similar to those of an alcoholic extract of
violets. Saturation of an acid solution with alkali gives, however,
a yellow or, in very concentrated solution, a red colour instead of
green. Dry distillation with soda gives a crystalline sublimate
soluble in alcohol.and extremely soluble in ether.
Crystalline Chlorophyll.j—J. Borodin believes that he has
obtained the long-desired result of pure chlorophyll in a crystalline
form by slow evaporation of an alcoholic solution, though he has not
as yet been able to isolate the crystals. They are doubly refractive,
giving a beautiful green sheen in polarized light. Their physical
properties differ from those of the dark-green crystals of hypochlorin
hitherto obtained.
Crystals and Crystallites;— By the term crystallites A.
Famintzin designates structures which agree neither with crystals
nor with the organized products of living cells. They may be
arranged under four different types, connected by transitional forms.
The mode of formation of crystals was illustrated by artificial
crystals of potassium phosphate and magnesium sulphate. From
these the author established the following points: (1) The original
form of the crystal is not always its permanent form. (2) Crystals
are formed constituting the half or even the fourth of a double
rhombic pyramid. (3) Crystals do not always grow with flat surfaces,
* SB. Naturf. Gesell. Leipzig, x. (1883) pp. 97-101.
+ SB. “Vers. Russ. Naturf. u. Aerzte, Odessa, Aug. 25, 1883. See Bot.
Centralbl., xviii. (1884) p. 188. -
{ SB. Vers. Russ. Naturf. u. Aerzte, Odessa, Aug. 24, 1883. See Bot.
Centralbl., xviii. (1884) p. 158.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 779
growth frequently taking place by means of irregular prominences.
(4) Crystals exhibit a splitting both transverse and longitudinal.
Spherocrystals,*—A. Hansen’s extended paper on this subject is
now published. A preliminary notice of it was given ante, p. 416.
Formation and Resorption of Cystoliths.t—Continuing his pre-
vious investigation of cystoliths, J. Chareyre has examined chiefly
those of Urtica Dodartii, U. pentandra, Oannabis sativa, Acanthus
mollis, A. lusitanicus, Thunbergia alata, and Andrographis paniculata,
grown in different soils, in darkness and in light. He finds all the
seeds of Urticaces examined before germination to contain reserves
of food-materials composed entirely of aleurone-grains, in each of
which is a globoid; and this is also the case with the seeds of
Acanthacex, except those of Acanthus and of Hewacentris coccinea,
which have no cystoliths, and in which the reserve food-material
consists for the greater part of starch-grains. No portion of these
reserves contributes to the formation of deposits of calcium car-
bonate, whether as cystoliths or in any other form. Nor are they
employed in the formation of crystals of calcium oxalate, which
do not occur in the plants under examination during or in the
period following germination, When grown in pure silica the
cystoliths do not attain full development; the pedicle is formed, but
does not develope cellulose at its apex, and always dies away when
entirely deprived of lime. Ordinary soil and soil formed of pure
calcium carbonate are about equally favourable to the formation of
cystoliths. When grown entirely in the dark, the seeds contain only
rudimentary cystoliths in which is no calcium carbonate.
In reference to the influence of the death or etiolation of the leaf
on the quantity of lime contained in the cystoliths, the author found
that in the Acanthaces etiolation, and even death, has no effect on
their formation. Among the Urticaces, and especially Ficus elastica,
darkness causes, after from 10 to 15 days, complete disappearance
of calcium carbonate in the cystoliths, this disappearance being
connected chiefly with the cessation of the function of the chloro-
phyll. The carbonate is not converted into bicarbonate; and a
disappearance takes place of calcium oxalate as well as carbonate.
The lime has entered into combination with some other acid, which
is probably pectic acid; it disappears from the leayes, and passes
into the stem, at least partially, in the form of calcium pectate,
Development of Raphides.t— A. Poli has investigated the for-
mation of the raphides contained in the cellular tissue of the bulb of
Narcissus intermedius, where they are always accompanied by a strong
development of mucilage. They occur in longitudinal rows of cells,
and in older examples are always imbedded in mucilage resulting
from the deliquescence of the transverse walls, which mucilage escapes
* Arbeit. Bot. Inst. Wiirzburg, iii. (1884) pp. 92-122 (3 figs.).
+ Bull. Soc. Bot. France, xxx. (1883) Sess. Extr., pp. vili—xii. Cf. this
Journal, iii. (1883) p. 389.
+ Nuoy. Giorn. Bot, Ital., xvi, (1884) pp. 56-9 (1 pl.), 3 9
¥
780 SUMMARY OF CURRENT RESEARCHES RELATING TO
from the plant in great quantities when wounded. In the young
state only a single bundle of raphides is found in each cell, later they
are much more numerous.
Here and there, in specimens preserved in alcohol, applied to the
walls of the cells which contain the raphides were found solid spherical
bodies of a yellowish colour and finely granular structure. The
formation of these bodies was unquestionably due to the alcohol;
and they probably arise from some gummy modification of the
mucilage.
New Vegetable Pigment.*—A Rosoll finds in the involucral
bracts of several species of Helichrysum a hitherto undescribed colour-
ing substance, to which he gives the name helichrysin. It tinges
the protoplasm, is soluble in water and alcohol, and is turned a
purple-red by both acids and alkalies.
The same writer also describes methods for detecting saponine
and strychnine in vegetable tissues. The first is easily recognized
by the action of sulphuric acid, which it colours first yellow, then
red, and finally reddish-violet. It occurs in the living cells dissolved
in the cell-sap. Strychnine is coloured an intense violet-red by
potassium bichromate and sulphuric acid. It occurs in all the cells
of the endosperm of Strychnos nux-vomica and S. potatorum dissolved
in a fatty oil.
Fish caught by Utricularia.j—G. E. Simms has discovered that
newly hatched fish are caught and killed by the bladder-traps of
Utricularia vulgaris, ‘They are mostly caught by the head, which is
pushed as far into the bladder ag possible until the snout touches its
hinder wall. The two dark black eyes of the fish then show out
conspicuously through the wall of the bladder. By no means a few
of the fish, however, are captured by the tail, and in several instances
a fish had its head swallowed by one bladder-trap and its tail by
another. :
Prof. H. N. Moseley ¢ thinks it probable that the fact described
by Darwin (that the larger of the two pairs of projections composing
the quadrifid processes by which the bladders are lined project
obliquely inwards and towards the posterior end of the bladder) has
something to do with mechanism by which the fish become so deeply
swallowed. The oblique processes, set all towards the hinder end of
the bladder, look as if they must act, together with the spring-valves
of the mouth of the bladder, in utilizing each fresh struggle of the
captive for the purpose of pushing it further and further inwards.
* Anzeig. K. Akad. Wiss. Wien, 1884, Nos. 7,9, See Bot. Centralbl., xviii.
(1884) p. 94.
+ Nature, xxx. (1884) pp. 81 and 295-6 (8 figs.).
t Ibid., p. 81.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 781
B. CRYPTOGAMIA.
Cryptogamia Vascularia.
Anatomy of Vascular Cryptogams.*—P. Van Tieghem has
studied several points in the anatomy of vascular cryptogams, recent
and extinct. The secondary tissues of cryptogams, like those of
phanerogams, proceed normally from two concentric generating
layers ; an external one in the cortex, forming bark outwardly, and
secondary cortex inwardly; an inner one in the central cylinder,
intercalated in the liber and in the xylem of the primary vascular
bundles, producing secondary liber outwardly, and secondary wood
inwardly. The normal subero-cortical generating layer is well de-
veloped in the stem (Botrychiwm, Helminthostachys), root (Botrychium,
Helminthostachys, Angiopteris, Marattia), and leaves (Botrychium,
Angiopteris, Marattia). The normal libero-ligneous generating layer
is developed both in living ferns (Botrychium, &c.) and in extinct
vascular cryptogams, as Sphenophyllum and Sigillaria. In addition
to these normal layers we find in certain species two other abnormal
generating layers: one external to the primary vascular bundles
(Zsoetes), and one interior to the primary vascular bundles (Boiry-
chium).
The author also describes several anomalies in the primary
structure of the root, viz. in the principal trunk and in the branches
of a dichotomous root.
Fertilization of Azolla.j—E. Roze has studied the structure of
the androspores (microspores) and gynospores (macrospores) and the
mode in which fertilization is effected in Azolla filiculoides, but
without adding anything fresh of importance to what is already
known. He observes that the barbed hairs attached to the “ massule ”
as they escape from the androsporangium do not occur throughout
the whole genus, being wanting in Azolla pinnata and nilotica. The
internal membrane of the gynosporangium, which remains attached
to the gynospore in the form of a funnel, appears to play an important
part in fertilization in facilitating the access of the antherozoids.
Muscinee.
Male Inflorescence of Mosses.{—H. Satter confirms the observa-
tions of Leitgeb and Kiihn in the case of Fontinalis and Andreca, that
the axil of the shoot is used up in the formation of the antheridial
receptacle, Leitgeb regarding this to be the rule with mosses. Tho
author shows that this is also the case with many Bryines, also
with Phascum and Archidium, which display apparent exceptions to
the rule.
In Phascum cuspidatum the last three segments and the apical cell
* Bull. Soc, Bot. France, xxx, (1883) pp. 169-80,
+ Ibid., pp. 198-206 (1 fig.).
t Ber. Deutsch. Bot. Gesell, ii. (1884) pp. 13-9 (1 pl.).
782 SUMMARY OF OURRENT RESEARCHES RELATING TO
form antheridia; behind the three leaves which are formed earlier
lateral shoots arise, or more often behind the youngest of them only,
and always behind the cathodal half of the leaf-forming segment.
After the formation of usually only three whorls of leaves, these pass
over to the formation of archegonia. In the leaves behind which the
shoots arise the formation of a midrib is suppressed, and they are
subject also to a variety of displacements in their insertion. The first
of the archegonia is formed out of the apical cell, the three or four
others out of the youngest segments. When the sexual organs are
mature, the female branch projects only slightly above the male
inflorescence; it is only after impregnation that any considerable
elongation takes place, by which the male inflorescence is pushed to
one side, or comes to stand in the fork, and is then surrounded by
two involucral leaves.
The process is the same in Archidium phascoides, only that there
is no considerable elongation of the female shoot; and hence the
archegonia and antheridia are apparently inclosed in a common peri-
cheetium composed of involucral leaves.
The same relative position of the sexual organs is exhibited by
Pottia subsessilis, P. cavifolia, P. truncata, P. minutula, P. Heimit,
Distichium inelinatum, Desmatodon obliquus, D. Laureri, and Oreas
Martiana. There is in these cases no doubt that the antheridial
receptacle is the termination of the main axis, and that is pushed
aside and overgrown by the elongation of the female branch.
A modification of this arrangement is exhibited by many species,
as Orthotrichum crispulum, O. Hutchinsie, Bartramia Halleriana,
B. pomiformis, Amblyodon dealbatus, &c., where the lateral shoots do
not arise immediately beneath the male inflorescence, but in lower
whorls of the male shoot. Hither these lateral shoots form archegonia
at once, or antheridia are again formed through several generations
of shoots, archegonia only in a later generation. In Amblyodon these
last branches are not always exclusively female, but have often sexual
organs of both kinds united in the same inflorescence. The author
considers that such a hermaphrodite inflorescence consists of two
independent shoots, the female one being formed immediately beneath
the antheridium-bearing segments, without producing any vegetative
segments, proceeding directly to the formation of archegonia; this
view being confirmed by transitional forms.
Lesquereux and James’s Mosses of North America.*—This book
includes all the mosses which are known on the North American
continent within the limits of the United States and northwards.
900 species are dealt with, a very large portion of them being
EKuropean. The classification does not diifer materially from that of
Bruch and Schimper (used in Wilson’s ‘ Bryologia’). The definitions
of species and genera are commendably full and clear, and the authors
have avoided establishing or admitting species upon a slender founda-
tion of differential character.
* Lesquereux, L., and T. James, ‘Manual of the Mosses of North America,’
447 pp: and 6 pls. 8vo, Boston, 1884.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 783
Fungi.
Supposed Absorption and Disengagement of Nitrogen by Fungi.*
—G. Bonnier and L. Mangin detail a series of experiments by which
they claim to have proved that the statement that fungi both absorb
and give off nitrogen while in a state of vegetative activity is founded
on error. The process of respiration consists solely in a disengage-
ment of carbon dioxide.
Fungus parasitic on Drosophila.t—The Rev. J. L. Zabriskie
describes Appendicularia entomophila Peck, a new fungus parasitic on
the fly Drosophila nigricornis Loew. It is closely related to the
Spheronemei of the Coniomycetes. Like Spheronema, the fruit has
a bulbous conceptacle, surmounted by a long beak perforated at the
apex, where the spores ooze out in a globule; but, unlike any de-
scribed Spheronema, this has the conceptacle seated* upon the broad
summit of a pedicle as long as the conceptacle itself; and also on one
side of the summit of the pedicle and at the base of the conceptacle,
it has an erect, leaf-like appendage, with strongly serrate margins,
like a white-elm leaf folded along its midrib. The pores are slender,
pointed at each end, and divided by a septum into two unequal
cells, one cell being twice as long as the other. The total length
of the fruit is from +02 to ‘03 in., and that of the spores from -001
to ‘002 in. The conceptacles of the fungus project directly from
different points of the surface of the fly; so that they are found in
all positions—erect, horizontal, and dependent. They grow some-
times singly, but oftener in clusters of two, three, or more, and are
found most frequently on the tibie of the hind legs, but also springing
from the inner posterior surfaces of the abdominal rings, from the
costal vein of the wing, from the head, and from the thorax. One
fly had about fifty of these conceptacles on various parts of the body
and limbs.
Peronosporee.t—M. Cornu gives (1) a monograph of the parasite
of the lettuce, Peronospora gangliiformis, (2) an important memoir on
the Peronospora of the vine. In both memoirs the best modes of
treatment are discussed for checking or warding off the disease.
Vine-mildew.$—E. Prillieux has observed on Peronospora viticola
reproductive bodies of a peculiar kind which he regards as probably
intermediate between the ordinary conidia and oogonia. They appear
in the same position as the conidia, emerging from the stomata of the
leaf, and consist of short filaments terminating in pear-shaped bodies
considerably larger than the ordinary conidia and separated from the
pedicel by a septum. Their germination has not been observed.
The author is of opinion that the ordinary “rot” or “ grey rot”
of the American vines is produced by Peronospora viticola, and not by
* Bull. Soc. Bot. France, xxxi. (1884) pp. 19-22.
+ Science, iv. (1884) p. 25.
¢ Cornu, M., ‘ Observations sur le Phylloxera et sur les parasitaires de la
vigne.’ See Bull. Soc. Bot. France, xxx. (1883) pp. 36-8.
§ Bull. Soc. Bot. France, xxx. (1883) pp. 19-24, 228-9.
784 SUMMARY OF CURRENT RESEARCHES RELATING TO
Phoma wvicola, as had previously been supposed ; although the latter
fungus undoubtedly makes its appearance in the berries or seeds
which have already been attacked by the Peronospora, but it plays
only a secondary part.
The germination of the oospores of P. viticola, has further been
observed by Prillieux. On germinating the oospore gives rise to a
branching tube which bears a number of conidia.
New Theory of Fermentation.*—E. Cocardas propounds the
strange theory that all the different kinds of fermentation—which are
as numerous as the different kinds of protoplasm—are due to the
action of a single organism, Penicillium, which appears, according to
its vital conditions, in the various forms of Bacterium, Bacillus,
Spirillum, Zooglea, Hygrocrocis, Leptomitus, Torula, Byssus, Mucor,
Aspergillus, Penicillium, Micrococcus, Microderma, Saccharomyces, &e.
Microbes in Human Saliva.t—A. F. Rasmussen has made a
careful examination of the micro-organisms found in the saliva of
healthy men, with the following results.
The sources of these microbes—mould spores, ferment-fungi, and
bacteria—are the air and the food ; some disappear immediately, while
others remain and undergo further development. 'The temperature
of the mouth, 36°-37° C., is very favourable for their development,
nutrient substances and oxygen being also always present in great
abundance. The organisms are especially abundant at the outer side
of the base of the back teeth, especially in the upper jaw, where a
thick layer of tough mucilage is always found in the morning, and for
some time after a meal. Carious teeth also breed large quantities
of these organisms.
The author found none of the methods previously used for the
culture of these organisms satisfactory ; culture on a solid substratum
he always found the most advantageous. The gelatine used for the
purpose was placed in bulbs with a large bottom, so as to give as
large a surface as possible. The staining employed was sometimes
Koch’s method, sometimes potassium biniodide, which however caused
great changes in the size of the objects. Thus the sporiferous
segments of Clostridium polymyxa measured 4—6 « before, 2-2 to 2°4
after staining. The reagent for Leptothriz employed was potassium
biniodide with a small quantity of hydrochloric acid.
The bulbs and test-tubes used were purified by concentrated
sulphuric acid and distilled water, or with dilute (0-1 per cent.) solu-
tion of corrosive sublimate; and the wad-plugs used to close the
apparatus were sterilized by a temperature of 110-120° C. For
culture in nutrient fluids the author used the bulbs recommended by
Salomonsen ; various fluids were used, as human urine diluted with
water and boiled for ten minutes, then filtered and neutralized with
sodium carbonate, bouillon, solution of peptone, beer-wort, solution of
* Bull. Soc. Bot. France, xxxi. (1884) pp. 12-8.
+ Rasmussen, A. F., ‘Om Dyrkning af Mikroorganismen fra Spyt af sunde
Menesker’ (Danish) 136 pp. (2 pls.). See Bot. Centralbl., xvii. (1884) p. 389.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 785
potassium albuminate, prepared by Lieberkiihn’s method, &e. For
conveying bacteria from one vessel to another, finely drawn-out glass
capillaries were used, first sterilized in a flame.
The author describes the culture of the microbes on potatoes,
turnips, and on rye-bread; and rules are given for the preparation of
the nutrient substance, the method of Koch and Brefeld being essen-
tially followed. After a longer or shorter time small patches, dots,
elevations, cushions, and similar structures arise, due to the microbes
propagated from the saliva. These may be either (1) white moist
opaque elevations—micrococci and bacteria, or (2) grey, dry, some-
what transparent patches—bacilli, colonies of a leptothrix-ferment, or
oblong cells; torula and round saccharomyces-cells constitute a
transition between the two; Penicillium glaucum, Oidium lactis, and a
few species of Mucor were also met with, but the colonies of these
forms are very easily confounded with those named before.
Culture on nutrient gelatine closely resembles that on potatoes ;
but many of the cultivated organisms deliquesce on the surface of
gelatine; this is the case with the chromogenous bacteria, the spori-
ferous bacilli, Penicillium, and Cladosporium. In the gelatine-culture
other phenomena also present themselves. Some forms grow down-
wards towards the bottom of the vessel, and form wedge-shaped
figures; torula puts out lateral branches from these wedges; other
forms spread out horizontally over the bottom; Micrococcus luteus
forms delicate pellicles, from which threads branch vertically down-
wards; Bacillus Ulna forms a kind of diffuse infiltration, which
descends into the gelatine and decomposes it on the surface. Culture
upon gelatinized serum presented no very distinct peculiarities.
As regards the systematic position of the microbes observed, the
author speaks first of the Zygomycetes, Mucor racemosus and
stolonifer ; also M. spinosus, new to Denmark, but observed only
once. In all cases they had the faculty of forming torula-cells.
Among Ascomycetes, Penicillium glaucum and album were observed,
and among Hyphomycetes, Cladosporium herbarum, and Oidium lactis,
the latter being one of the most frequent of the saliva-organisms.
Torula was also found abundantly in nutrient fluids, and on gelatine
and potato; when transferred to solutions of grape-sugar or to diluted
urine, it exhibited no power of fermentation or of inverting, Under —
the name “torulose cells” (hefedhnliche Zellen) the author describes
colourless or reddish cells, either roundish or elongated, and also
peculiar species of Saccharomyces, which are only stages of develop-
ment of higher fungi. One of these flesh-coloured species appears to
be allied to Cohn’s Saccharomyces glutinis ; a second unnamed form
was 9-11 p long, 4 » broad, with drops of oil imbedded in the proto-
plasm; a third consisted of round and elongated cells arranged in
colonies, 11 » long, and 3 » broad, with no drops of oil. Saccharo-
myces apiculatus was not observed.
With regard to the Schizomycetes, the author considers that the
view of Zopf that the different forms are stages of development of the
same organism is true only of Leptothrix, which may go through all
the yarious forms, while all the other Schizomycetes have one form
786 SUMMARY OF CURRENT RESEARCHES RELATING TO
only. Of these constant forms he finds Bacillus Ulna, Clostridium
butyricum, O. polymyxa, and several others not named, but no constant
bacterium, and only once a coccus.
Of Leptothria three distinct forms are described in detail, one of
them chromogenous. Two of these he regards as comprised under
L. buccalis, which together with spirillum, vibrio, and Spirocheete
denticola, causes the mucilage of the teeth.
Of other chromogenous forms the author finds Micrococcus luteus,
two unnamed, and Bacillus Hansenii, a new species. Cultivated on
potato, this form grows with extraordinary rapidity, almost to the
exclusion of all others.
Experiments are described which lead to the conclusion that the
fluid in some cases contains micro-organisms when it enters the
mouth from the ductus stenonianus; but that the air expired from
the lungs is free from them.
Microbia of Milk.*—F. Hiippe has made a detailed examination
of the microbia of milk, which can, he states, be completely sterilized
by a temperature of 75°-100° C. He describes in detail the bacteria
connected with the fermentation of milk, their biological relationships,
and their chemical action on the milk. The bacilli of butyric fer-
mentation are also described, the organisms of blue milk, other
pigment-forming bacteria, mucilaginous milk, and Ozdium lactis. The
author holds very strongly the view of the constancy of the bacteria
of milk.
Microbe of ‘‘ Morbillo.”+—-M. Lanzi has investigated the microbe
characteristic of this infection which he finds especially in the desqua-
mated scales of the skin and in the urine. He considers it to be a
species peculiar to this complaint, to which he gives the name
Bacterium morbilli with the following characters :—Cells round or
elongated, colourless, motile, isolated or united into chains of various
lengths, composed of two or more cells, straight or more often curved,
and even spiral: cells, 0:8-1-0 « in diameter, with the length vary-
ing from this to double as much; no zoogloea-form was observed ;
propagation by fission in one direction, and then forming spores.
Occasionally a large bacillus-form was assumed. The best staining
reagent was found to be methyl-violet. Bacterium morbilli has no
power of causing fermentation in the urine like Micrococcus uree.
Without considering the question decided, the author leans to the
opinion that it is the cause, and not merely the accompaniment of
the disease.
Bacillus of Cholera.{—T. R. Lewis denies the validity of Dr.
Koch’s conclusions as to the “ comma-shaped ” bacillus being the cause
of cholera, as bacilli identical in size, form, and in their reaction
with anilin dyes with those found in choleraic dejecta are ordinarily
present in the mouth of perfectly healthy persons.
* MT. K. Gesundheitsamtes, v. p. 309. See Naturforscher, xvii. (1884)
p. 201.
+ Bull. Accad. Med. Roma, ix. (1883) No. 7.
{ Nature, xxx. (1884) pp. 513-5.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 787
Rabies.—The Government committee appointed to inquire into
the experiments of M. Pasteur, report that his statements have been
entirely borne out. Inoculation with the attenuated virus of hydro-
phobia gives a dog immunity from the disease, just as similar treat-
ment preserves a sheep from charbon. All the 23 dogs submitted by
M. Pasteur as having been thus inoculated have resisted the strongest
virus on inoculation, whereas the majority of the 19 non-inoculated
dogs have succumbed. Of the latter, six were bitten by mad dogs,
three of them becoming mad, eight were subjected to intravenous
inoculation, all becoming mad, and five to inoculation by trepanning,
all becoming mad. The result is decisive; but the committee will
now inoculate a large number of fresh dogs, and will compare these
with an equal number of dogs not inoculated. It will likewise investi-
gate the question whether, after a dog has been bitten, inoculation
with the attenuated virus will prevent any consequences from the
bite.
Etiology of Tuberculosis.*—Dr. G. N. Sternberg has repeated
Koch’s inoculation experiments, and is able to confirm him as to the
infectious nature of tuberculosis; also as to the presence of the
bacillus discovered by him, in tubercle nodules in the lungs and in
tuberculous glands of inoculated rabbits and guinea-pigs (inoculated
with sputum containing the bacillus from a phthisical patient).
The experiments of Formad of Philadelphia, by which he claims to
induce tuberculosis in rabbits as a result of the introduction into the
cavity of the abdomen of finely powdered inorganic material, have
also been repeated, with an entirely negative result so far as the
production of tuberculosis is concerned.
The conclusion is therefore reached that the bacillus of Koch is
an essential feature in the etiology of the infectious disease, tuber-
culosis.
Bacteria and Minute Algx# on Paper Money.{ —J.Schaarschmidt,
in consequence of Prof. Reinsch’s discovery t of bacteria and alge on
coins, has examined Hungarian bank and State notes and Russian one-
rouble notes, and finds schizomycetes and alge on all of them even
upon the cleanest.
The vegetation of paper money is, as the result of his researches,
composed of the following : Micrococcus, Bacillus, Leptothriz (various
forms), Bacterium termo, and Saccharomyces cerevisie. Also, very
rarely, Reinsch’s Chroococcus monetarwm and Pleurococcus monetarum.
Grove’s ‘Synopsis of the Bacteria and Yeast Fungi.’ §— This
book reaches us too late to say more than that it is a very handy and
well-arranged synopsis of the Schizomycetes and Saccharomycetes,
which cannot fail to be of invaluable assistance to microscopists
* Abstract of paper read before Section F (Biology) of the Amer. Assoc. Ady,
Sci., Philadelphia, Sept. 9, 1884.
+ Nature, xxx. (1884) p. 360.
¢ See this Journal, ante, p. 428.
§ Grove, W. B., ‘A Synopsis of the Bacteria and Yeast Fungi and allied
species.’ 8vo, London, 1884, vi. and 112 pp. (87 figs.).
788 SUMMARY OF CURRENT RESEARCHES RELATING TO
interested in its subject, and not the less so that our knowledge
regarding these organisms is at the present time in so scattered and
undigested a condition.
Protochytrium Spirogyre, a new Myxomycete(?).*—A. Borzi
describes a parasitic organism of very low organization, which he
finds in the cells of Spirogyra crassa and of a few other nearly allied
species of alga, rapidly destroying the contents of the cells and
causing complete disintegration of the filaments, the cell-walls them-
selves ultimately entirely perishing. The minute masses of proto-
plasm of which it is composed are completely destitute of cell-wall,
and display amceboid motions, but without any pseudopodia. They
derive their nutriment directly from the surrounding protoplasm, and
may be regarded as plasmodia of very reduced dimensions. They
are composed of homogeneous protoplasm, within which are very fine
granulations, and have, therefore, all the characters of an organiza-
tion the simplest that can be imagined. ‘They compose a true jalo-
plasm in the sense of modern histologists, constantly altering its
form in consequence of its amceboid motions. The granulations are
frequently disposed round a small transparent central areole, which
represents a true vacuole. It is, however, entirely destitute of true
nuclei, the minute granulations wanting all the characteristic struc-
ture of these organisms. The central vacuole is constantly altering
its position, and alternately contracting and expanding. The princi-
pal, if not the sole, agent in these amceboid movements appears to
be the superficial protoplasmic layer. The growth of these organisms
is rapid, and they attain a diameter of about 40 » in twelve hours.
The process of nutrition may be divided over two distinct
periods. In the first the nutriment, derived from the surrounding
substratum, passes directly into the body of the parasite. In the
second period, the substances, already ingested and deposited, become
somewhat elaborated and digested. These two phases can be well
followed under the Microscope.
When one of the plasmodia comes into contact with a band of
chlorophyll, it slowly penetrates into its interior. A small portion
of the nutrient substance, consisting of protoplasm containing chloro-
phyll and of starch-grains, becomes at length entirely imprisoned in
the mass of the plasmodium. 'The ingested substance retains for a
very short time its original properties. The chlorophyll soon loses
its green colour; the granules of starch are the last portion to be
completely absorbed. An excretory portion which is not digested
is finally expelled.
The vegetative activity of the plasmodia ceases on the commence-
ment of the reproductive period; they attain a state of quiescence,
and the formation of zoosporangia commenecs. The peripheral
layer of protoplasm becomes thinner and tends to merge in the
internal portion; its motility at the same time disappearing alto-
gether. After numerous internal changes in the structure of the
protoplasm, the contents divide by successive bipartitions, either a
* Nuoy. Giorn. Bot. Ital., xvi. (1884) pp. 5-32 (1 pl.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 789
portion or the whole of the protoplasm being used up in the forma-
tion of zoospores, which process is a very rapid one. On escaping
from the zoosporangium these bodies are minute pear-shaped or
ovoid masses of protoplasm, containing granulations, and not invested
with a cell-wall, provided at one end with a flagelliform cilium, and
also with a contractile vacuole. In some cases the zoospores are
unable to escape from their parent cell, and transform themselves
directly into new zoosporangia. Hither the ordinary zoospores or
those derived from these secondary zoosporangia, after moving about
actively for half an hour, lose their cilium, and become transformed
into an ordinary amceboid mass of protoplasm, with movements due
to contractions and dilations, in which condition they may be
described as myxamebe. In this state they not unfrequently come
together and coalesce, the two vacuoles remaining for a time dis-
tinct, but finally uniting. The original plasmodia are formed either
from a single myxameeba, or result from a fusion of several ; and these
may then propagate themselves for several generations before the
formation of zoospores.
Instead of the production of zoospores, the period of vegetative
activity of Protochytrium is frequently closed by the formation of
cysts, or true encysted plasmodia, especially at the period when the
host naturally dies. These are cells with double walls, and with a
considerable space between the outer and inner walls; this space is
filled with a transparent fluid, often containing small remains of
nutrient substance not completely digested. The ordinary diameter
of the cyst itself is from 15 to 25 yw, that of the external envelope
from 30 to 40 w. This external envelope displays many of the pro-
perties of fungus cellulose. The internal contents consist of a dense
finely granular protoplasm. These cysts are formed within the cells
of the host, and when they decay, fall to the bottom of the water,
where they germinate after a period of rest, and develope into
myxamcebe. ‘These again enter the cells of the host by penetrating
through the cell-walls, in the same manner as the germs of many
Chytridiacez.
As regards its systematic position, Protochytrium displays on the
one hand affinities with the Myxomycetes, and on the other hand
with such genera of Chytridiacee as Woronina, Rozella, and Olpidi-
opsis ; but the author considers the entire absence of a cell-nucleus
to be a point of so great morphological importance that it must for
the present be referred to Klein’s family of Hydromyxacee, along
with the forms of Monas described by Cienkowski and Hickel, and
also Vampyrella, Monadopsis, and Protomyxa.
Lichenes.
Substratum of Lichens.*—O. J. Richard, besides combatting the
theory of an algo-lichenic association, holds that the nature of the
substratum, whether calcareous, siliceous, metallic, organic, or neutral,
* Actes Soc. Linn. Bordeaux, 88 pp. See Bull. Soe, Bot. France, xxx. (1883)
Rey. Bibl., pp. 105-7,
790 SUMMARY OF CURRENT RESEARCHES RELATING TO
is of small consequence to the lichen, which derives no nutriment, but
merely support therefrom. Nor does the author agree that the
chemical composition of the thallus varies according to the nature of
the substrata.
Hymenolichenes.*—This section of lichens was established by
Mattirolo from the genus Cora, and depends on the symbiosis of an
alga with a fungus belonging to the class of Hymenomycetes. F.
Johow has critically examined the group in its native country of
Venezuela and the West Indies, and includes in it the four following
genera :— Cora, Rhipidonema, Dictyonema, and Laudatea gen. noy.
The first three genera must be regarded, from their habit and the
lamination of their thallus, as heteromerous foliaceous lichens, but
differing from all other genera in the entire absence of a solid cortex
and in the unusually complete investment of the alge which perform
the function of gonidia. Laudatea is distinguished by its peculiar
cespitose habit, and by the segmentation of the thallus connected
with it into a saprophytic mycelium and green stems composed of
bundles of gonidia invested by fungus-hyphe.
The systematic position of the Hymenolichenes is among the
Thelephorea, and in near relationship to Thelephora, Corticium, and
Hypochnus. The only organs of reproduction which they possess are
sporiferous basidia growing on the under side of unilateral pilei, or on
crustaceous receptacles (Laudatea). Nylander’s statement of the
presence in Cora of apothecia has not been confirmed. The saprophytic
mycelium and crustaceous receptacle of Laudatea find their analogue
in numerous species of Thelephora and Corticitum. The green foliaceous
thallus of Cora is homologous to the receptacle of Thelephora.
Algee.
Fresh-water Pheospore.t—Under the name Lithoderma fontanum,
KE. Flahault describes a fresh-water phesosporous alga from the neigh-
bourhood of Montpellier. It agrees with other species of the genus
in having the zoosporangia naked and superficial. The thallus is
closely adherent to the substratum, recalling that of Melobesia or
Coleochete. The zoospores are ovoid, unequilateral, with a red eye-
spot and two unequal cilia inserted on the concave side of the zoospore,
and directed one forwards, the other backwards. They germinate
directly, without conjugation.
Nostoc.$—C. Flahault has had the opportunity of examining the
structure of the rare Nostoc flagelliforme, growing in the neighbour-
hood of Montpellier, described by Berkeley and hitherto known only
from Texas. He regards it as identical with the MNematonostoc
rhizomorphoides of Nylander, which genus must therefore disappear.
Spores were not observed, but hormogonia frequently. Nostoc flagelli-
* SB. K. Preuss. Akad. Wiss. Berlin, 1884 pp. 113-28; also Pringsheim’s
Jahrb. f. Wiss. Bot., xv. (1884) pp. 361-409 (5 pls.).
+ See this Journal, ii. (1882) p. 542.
t} Comptes Rendus, xcviii. (1884) pp. 1389-91.
§ Bull. Soc. Bot. France, xxx. (1883) pp. 89-96 (1 pl.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 791
forme must also disappear as a species, being merely a variety of
N. ciniflorum Vauch.
Flahault further identifies Nostoc coriaceum Vauch. as a form of
N. ciniflorum.
New Chromophyton.*—M. Cornu describes an alga coloured by
a yellow pigment found in a spring of fresh water, in company with
Navicula, and possessing a siliceous coat similar to that of diatoms.
He regards it as nearly allied to Woronin’s Chromophyton Rosanoffii,t
differing from that species in its siliceous envelope, and in the posses-
sion of stalked bodies which may be sporangia. He proposes for it
the provisional name Chromophyton Woronini.
Wolle’s Desmids of the United States.{—The Rev. F. Wolle’s
work on the desmids of the United States will be found useful by
English cryptogamists who are not in possession of Ralfs’ work.
Eleven hundred coloured figures are given illustrating all the species
and varieties described in the text.
New Diatoms.—Diatoms from Stomachs of Japanese Oysters.§
—F. Kitton describes some new diatoms taken by Mr. G. Sturt from
the stomachs of some “tinned” oysters from Japan, sent to the
Fisheries Exhibition, viz., Aulacodiscus Sturtii and Amphipleura
pellucida var. rectus. Nearly 90 other marine species as well as a
considerable number of fresh-water species from the stomachs were
identified by Mr. E. Grove.
Mr. Sturt’s directions for examining the stomachs of oysters, &c.,
are as follows :—“ After opening the tin and pouring off the liquid
contents, I empty out the oysters and pick out the stomachs
(which look like dark little sacs, and as a rule are free, or only
partially surrounded by a little fatty matter, which is easily taken
off), I then heat in a glass to boiling point five or six ounces of
nitric acid, in which I drop one by one the stomachs, waiting until
each is dissolyed before adding another, After all have been dis-
solved I add an ounce of hydrochloric acid, and continue the boiling
for five minutes, dropping in at intervals a little bichromate of potash,
I now fill up the flask with hot water and empty the whole into a
large beaker, filling up with the hot water (the fat rises to the
surface, and on cooling congeals on the top, and is easily skimmed
off). I wash away the acid, using hot water, and boil in soap and
water according to Prof. H. L. Smith’s directions, If this does not
get rid of the organic matter, I boil in sulphuric acid and chlorate of
potash.” The water used for washing must be filtered rain or dis-
tilled water and free from all trace of acid,
Mr. Kitton also describes, from other localities, the following new
species :—Surirella carinata and Sceptroneis (?) clavus.
* Bull. Soc. Bot. France, xxx. (1883) Sess. Extr., pp. xciii—yv.
+ See this Journal, i. (1881) p. 100; iii. (1883) p. 108 and 863,
; Wolle, F., ‘ Desmids of the United States and list of Pediastrums.’ 168 pp.
and 53 pls. 8vo, Bethlehem, Pa., 1884.
§ Journ. Quek. Micr. Club, ii. (1884) pp. 16-23 (1 pl.).
792 SUMMARY OF CURRENT RESEARCHES RELATING TO
Structure of Diatoms.*—According to L. Reinhardt a form of
valve similar to that described by Miller in Triceratium, occurs in
many, if not all forms with areolated celi-wall.
The formation of the pedicel and of gelatinous colonies are
phenomena altogether analogous to those which occur in the palmel-
loid alge. In the Mastoglea colonies it is easy, when the formation
of jelly has not advanced beyond a certain extent, to observe a similar
system of intercalation of cell-walls as in Gloocystis. In the cell-wall
of Mastoglea and other similar forms, two layers can be distinguished,
an outer gelatinous, and an inner layer which retains its consistency
and structure. In the formation of the pedicel the outer layer
becomes locally mucilaginous. In those forms where an entire group
of individuals is attached to a single pedicel (as many species of
Synedra and Liemophora) longitudinal striz make their appearance on
the thick pedicel corresponding to the separate cells; these are made
distinctly visible by staining with hematoxylin.
The author also describes the formation of auxospores in Cocconeis
communis, Achnanthes longipes, and A. brevipes; in the first species
their development was followed out in several hundred specimens.
The auxospores are always formed by the conjugation of two in-
dividuals, never by rejuvenescence, as stated by Schmitz. The con-
jugating cells often open at different times, and the formation of the
mucilaginous bladders begins only with the coalescence of the con-
jugating masses of protoplasm. The nuclei of the conjugating cells
move slowly in the direction of the movement of the protoplasm
towards the anterior margin of the masses of protoplasm, and, a short
time after these commence to coalesce, a single much larger nucleus
is seen in the place of the two. Conjugation of the nuclei therefore
takes place here. ‘The author further describes the formation of the
perizone and of the cell-wall of the auxospore, the growth and bipar-
tition of the chromatophores, and the division of the auxospores into
two primary cells. In Achnanthes longipes the conjugation always
takes place in a very interesting way between two cells which are not
equivalent. One of these has always a long pedicel, whilst the other
is attached by a gelatinous disk to the upper end of the pedicel of the
first. When the protoplasmic masses of two cells coalesce, a mucila~-
ginous bladder is formed, which is connected only with the lower
valve of the stalked cell. Since this bladder is formed essentially
from the protoplasm of the stalked cell, it follows that that of the
other cell passes into the bladder of the first. The phenomena in
this species justify the regarding of the formaticn of auxospores by
conjugation as a process of sexual reproduction. In A. brevipes the
process is the same in its general features. The formation of auxo-
spores without conjugation is regarded by the author as a kind of
apogamy.
* SB. Vers. Russ. Naturf. u. Aerzte, Odessa, Aug. 27, 1883. See Bot,
Centralbl., xviii. (1884) p. 191.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 793
MICROSCOPY.
a. Instruments, Accessories, &c.
Albertotti’s Micrometer Microscope.*—Dr. G. Albertotti, jun.,
has designed the instrument shown in fig. 123, for the purpose of
measuring microscopic objects more satisfactorily than can be done
with either eye-piece or stage micrometer.
Fig, 123.
If the diverging plates of Helmholtz’s ophthalmometer are inter-
posed between the eye-piece and objective of a compound Microscope
in such a way that the axis of the plates is at right angles to the
axis of the Microscope, the effect of the plates on the apparent
* Aun. di Ottalmologia, xi. (1882) pp. 29-30 (1 pl.). -
Ser. 2.—Vou. LV. G
734 SUMMARY OF CURRENT RESEARCHES RELATING TO
position of an object seen through the Microscope will be the same as
when they are used without a Microscope, i. e. so long as the plates are
in one plane the image is unchanged in its position, but as soon as
the plates cross at an angle it will be separated into two images of
equal size, which are displaced in opposite directions. By turning
the plates through a sufficient angle the displacement can be so
arranged that the margins of the two images which are turned to each
other shall coincide, and a compound image is formed which, in the
direction of the displacement is twice as large as the original
one. For the same eye objective and eye-piece and for a constant
distance of both from the axis of the plates, the angle of inclination
to be given to the plates, in order to double the image, bears a fixed
relation to the size of the object and may therefore be used to
measure it.
If a table is prepared showing the values in mm. of the angles of
inclination of the plates, it is only necessary in measuring an object
to turn the plates until the image is doubled and ascertain the angle
between them, and the table will then give the dimensions.
In fig. 123 the square box between the eye-piece and objective
holds the Helmholtz plates which are rotated by the outer milled
head, the angles of inclination being read off on the large graduated
drums on each side.
It is claimed that by the use of this instrument those errors are
avoided which arise in the use of the eye-piece micrometer if the
image of the object does not exactly fall in the plane of the
micrometer divisions. ‘The angles can moreover be read with greater
precision than the micrometer divisions.
Baumann’s Callipers with Movable Microscope and Fixed
Micrometer.*—T. Baumann’s instrument (fig. 124), in which the
Microscope is movable and has a fixed micrometer in the eye-piece, is
not intended for such minute measurements as the preceding, but was
devised for cases for which a vernier is not sufficiently exact, while a
screw micrometer is too fine or not sufficiently rapid. It will read
to 0:04 mm. In a base plate A A, 200 mm. long, a central groove is
cut, along which moves the cylinder a. The upper edges of the
groove are bevelled off by a cylinder of the same diameter as a. The
cylinder moves freely along these without attachment of any kind, to
avoid errors of tension, &c. To one end of the cylinder is attached a
glass plate C, another glass plate B being fixed exactly parallel at the
end of A, the two plates forming the jaws of the callipers. The
cylinder is moved by the ivory handle at h. A plate u wis attached
to the former on one side, to which plate are fastened the two supports
g which carry the socket of a compound Microscope Jo (78 mm. high
and magnifying 50-60 times). The supports g rest on the base plate.
The socket is divided and the two halves are clamped by the milled
head m. 'The inside of the socket has a worm so that by turning the
ring k the Microscope is moved up or down for focusing.
The edge of the base plate is divided on silver for 150 mm. into
* Zeitschr. f. Instrumentenk., iv. (1884) pp. 149-52 (2 figs.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 795
0:2mm. The centimetres are numbered with large figures and the
millimetres by microscopic figures from 0 to 9. The approximate
position of the Microscope is read off by a pointer. One of the
smaller figures is always in the field of the view, which is 1°5 mm.
in diameter. At is a micrometer which can be rotated in azimuth.
Fic. 124.
wae”) 0
Its five divisions coincide with one of the scale as seen through the
Microscope, and each is therefore equal to a fifth of 0:2 mm. or
0°04mm. The divisions are preferably inclined, as shown in fig. 125.
The reading in this case is 4°936 mm. as the last line of the micro-
meter (reading from right to left owing to the inversion of the image)
is 3-4 divisions from the 4°8 mm. point of the scale. As each
division is 0°04 mm., 3°4 of these divisions = 0°186 mm. The
a. @.2
796 SUMMARY OF CURRENT RESEARCHES RELATING TO
coincidence of the 0 point of the scale with that of the micrometer is
obtained by the screws r and s acting on the plate u u, which is not
rigidly fixed to the cylinder a, but slightly movable.
Geneva Co.’s Microscope Callipers.—In the instrument, fig. 126,
(made by the Société Genevoise pour la construction d’Instruments
de Physique), 2 compound Microscope is made use of for measuring
minute thicknesses such as cover-glass, &c. It consists essentially of
a lever at one end of which are the jaws for holding the object to
Fig. 126.
be measured (shown in the figure with a piece of glass between
them), and the movement of which is amplified twelve times. At
the other end the lever carries a glass plate ruled with 120 divisions,
which is observed through a Microscope having a fixed micro-
meter in the eye-piece with 30 divisions. The jaws are opened by
the milled head on the box, and the extent of movement is indi-
cated by a scale with 120 divisions (corresponding to the glass plate),
which passes under the aperture seen at the top of the box. By the
eye-piece micrometer the principal divisions may be further sub-
divided. When open the jaws are 8 mm. apart; each of the principal
divisions represents therefore 1/40 mm., and the subdivisions
1/1200 mm. The mirror illuminates the divisions of the glass plate.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 797
Griffith’s Club Microscope. — Mr, E. H. Griffith writes us that
he has further improved the ‘ Griffith Club Microscope’ * as follows:
“The bar that holds the clips has a stiff spring over it. The front
of the bar is flattened. The clips may be turned back out of the way,
and when needed again the spring holds the clips down (or the bar
in position), Some have been made with an arrangement to push the —
bar either way, letting the bar pass through the stage-holder but
above it a nut gives the double clips a lateral motion and the spiral
spring keeps the bar steady. 'The double clips clasp the slide and
carry it with them. The lamp attachment has been improved
also.”
Nachet’s Class Microscope.—This (fig. 127) was intended by M.
A. Nachet to be passed round amongst the students in a class, being
at the same time very steady on the table. It can only be used in a
Fic. 127.
engi
iu
|
hi
horizontal position. The body-tube is focused by the rack and milled
heads at the top, while the stage and mirror, which slide on the
horizontal bar, are raised or lowered by the milled heads at the side of
the standard. The shifting of the object from right to left is effected
by the hands.
Nachet’s Microscope with Large Field.,—A. Gravis describes a
new Microscope by M. A. Nachet, of which the speciality appears to
be that it affords a larger field of view than usual in Continental
* See this Journal, iii. (1883) p. 113.
+ Bull. Soc. Belg. Micr., x. (1884) pp. 194-7,
798 SUMMARY OF CURRENT RESEARCHES RELATING TO
Microscopes, and is thus specially adapted for dissecting, examining
large sections, &c. The tube has an interior diameter of 29 mm.,
and the apparent diameter of the field measured at a distance of
250 mm. by means of the camera lucida is 200 mm. With the
ordinary Nachet No. 1 eye-piece this diameter is only 185 mm., and
with No. 1 Prazmowski 110 mm. There is a variable objective, which
when shortened gives a magnifying power of 15 with a working distance
of 28 mm. and real diameter of 13 mm. When extended these figures
are 23, 7 mm. and 8°5 mm. respectively.
Stephenson’s Aquarium Microscope.—This Microscope (fig. 128)
was designed by Mr. J. W. Stephenson for the examination of living
objects in an aquarium.
Fia. 128.
JTAVTAUTEALEUAEAAACCE LECTUS CET
TTA
we
A brass bar is laid across the aquarium, as shown in the woodcut.
To adjust it to aquaria of different widths the support on the left is
made to slide along the bar, and it can be clamped at any given point
by the upper milled head. The milled head at the side, by pressing
on a loose plate, fastens the bar securely to the aquarium.
Between the ends of the bar slides an arm carrying a sprung
socket, and the arm can be clamped at any given point of the bar.
Through the socket is passed a glass cylinder, cemented to a brass
collar at the upper end and closed at the lower by a piece of cover-
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 799
glass. Into this cylinder is screwed the body-tube of the Microscope
with eye-piece and objective, which are thus pr otected from the water
of the aquarium. The Microscope is focused by rack and pinion
(milled head just below the eye- -piece), and in addition the objective
is screwed to a draw tube so that its position in the cylinder may be
approximately regulated.
The arm of the socket is hinged to allow of the Microscope being
inclined in a plane parallel to the sides of the aquarium. ‘The lower
milled head clamps the hinge at any desired inclination. The socket
also rotates on the arm so that the Microscope can be inclined in a
plane parallel to the front of the aquarium. Thus any point of the
aquarium can be reached.
Swift and Son’s Oxyhydrogen Microscope. — This (fig. 129)
is suitable for use with ordinary objectives from 4 in. to 1/4 in.
The gas jet can be regulated for either parallel or convergent light
without the necessity of opening the lantern, it being mounted on
Fie. 129.